Curved secondary battery including electrode support and method for manufacturing same

Abstract

The present invention relates to a curved secondary battery including an electrode support that can operate without deformation, and a method for manufacturing the same. Curved cells manufactured using a curved cell production jig are produced in a round shape with a specific curvature. However, as the curved cells are repeatedly charged and discharged in a device to which the curved cells are attached, deformation of the curved cells occurs. To prevent such deformation of the curved cells, a support is formed inside the electrode assembly, and the curved cells can be operated in a device that requires energy without being damaged. The present invention also relates to a curved secondary battery including an electrode support that can operate without deformation, and a method for manufacturing the same. The curved secondary battery can maintain its shape even after repeated charging and discharging.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0125427, filed September 20, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a curved secondary battery including an electrode support and a manufacturing method thereof. More specifically, a curved cell manufactured in a curved cell production jig is produced in a round shape having a specific curvature, but the shape of the curved cell is deformed as the curved cell is repeatedly charged and discharged in a device to which the curved cell is attached. In order to prevent such shape deformation of the curved cell, a support is formed inside the electrode assembly, and the curved secondary battery including the electrode support can operate without shape deformation, allowing the curved cell to be operated in a device requiring energy without being damaged, and a manufacturing method thereof. [Background technology]

[0003] As the safety and capacity of rechargeable lithium secondary batteries have been improved rapidly, the number of devices using the lithium secondary batteries as an energy source has been increasing.

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

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

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

[0007] Curved cells formed with such curved surfaces are installed in devices that require energy, and as they are repeatedly charged and discharged, deformation occurs. A curved cell and its manufacturing method that can prevent this deformation and maintain the precise thickness and curvature that meets product specifications are required.

[0008] Korean Patent Publication No. 10-2015-0092669 discloses a configuration including a curved electrode assembly, an exterior material that seals the electrode assembly, and a reinforcing layer that is a curved plate positioned on the exterior material, in which the bending strength of the adhesive layer that bonds the reinforcing layer and the reinforcing layer is greater than the volume expansion force of the curved secondary battery.

[0009] However, this is different from the technology of the present invention in which an internal support is applied to prevent curvature deformation by being formed on a specific surface of the electrode assembly inside the pouch.

[0010] Korean Patent Publication No. 10-2015-0119664 discloses a curved electrode assembly, a pouch that seals the electrode assembly, a reinforcing portion formed on the side of the pouch so as to be continuous with the body portion, and a technology for determining the area, width, and curvature characteristics of the reinforcing portion.

[0011] However, there is a difference from the technology of the present invention in which an internal support is applied to the surface of the current collector where the electrode active material of the electrode assembly is not formed, to prevent curvature deformation.

[0012] Korean Patent Publication No. 10-2003-0096718 discloses a technology that includes a pouch that houses an electrode assembly including a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate, with at least a portion of the electrode leads connected to the positive electrode plate and the negative electrode plate respectively exposed to the outside, and at least one reinforcing member attached to all or a portion of the surface of the pouch, where the reinforcing member is a metal member.

[0013] However, this differs from the technology of the present invention in that an internal support having elastic restoring force at high temperatures due to repeated charging and discharging of the curved cell is applied, which is formed on a specific surface of the electrode assembly inside the pouch that houses the curved cell to prevent curvature deformation.

[0014] Japanese Patent Application Laid-Open No. 2000-251855 discloses a nonaqueous secondary battery comprising a battery element and an exterior film that encapsulates the battery element and has a moisture-proof layer and a synthetic resin layer, in which the edges of the exterior films are overlapped and joined together, and the exterior films are folded so that the joined portions overlap, thereby stacking four or more layers and crimping them together.

[0015] However, there is a difference from the technology of the present invention in that an internal support made of a thermosetting material is applied inside the pouch to prevent curvature deformation by being formed on a specific surface of the electrode assembly.

[0016] Therefore, in order to prevent curvature deformation, shape deformation, asymmetry, uneven thickness, and damage to the pouch and / or leads of the curved cell that may occur during the charge and discharge process of the curved cell, there is a need to develop a curved secondary battery including an electrode support that can operate without shape deformation and can be used in devices that require energy without damage to the curved cell by forming a support inside the electrode assembly, and a manufacturing method thereof. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Korean Patent Publication No. 10-2015-0092669 [Patent Document 2] Korean Patent Publication No. 10-2015-0119664 [Patent Document 3] Korean Patent Publication No. 10-2003-0096718 [Patent Document 4] Japanese Patent Application Laid-Open No. 2000-251855 Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention has been made to solve the above problems, and aims to provide a curved secondary battery including an electrode support that can operate without deformation and can be used in devices requiring energy without damage by forming a support inside an electrode assembly to prevent deformation of the curved cell, even though curved cells manufactured using a curved cell production jig are produced in a round shape with a specific curvature. However, as the curved cell is mounted on a device that repeatedly charges and discharges the curved cell, deformation of the curved cell occurs. [Means for solving the problem]

[0019] To achieve this object, the curved secondary battery according to the present invention may be a curved secondary battery including an electrode assembly (100) having a curved positive electrode / separator / negative electrode laminated structure, a cell case (200) that houses the electrode assembly therein, and a curved internal support (300) formed on at least one surface of the electrode assembly.

[0020] The electrode assembly may be a stack / folding type electrode assembly in which a stack type mono-cell, bi-cell, or full cell is sequentially wound around a separator sheet as a unit cell.

[0021] In addition, the inner support may be formed on the collector surface (110, 120) of the current collector forming the electrode, on which the active material layer is not formed.

[0022] In addition, the internal support may be formed on one or more longitudinal (y-direction) current collector sides (130, 140) of the stacked electrode assemblies.

[0023] The material of the internal support may be one or more selected from the group consisting of metal, ceramic, and polymer compound.

[0024] The polymer compound may be a thermosetting polymer compound.

[0025] The thermosetting polymer compound may be one or more selected from the group consisting of polyamide (PA), polyarylene ether (PPE), polyether ether ketone (PEEK), polyimide (PI), and polytetrafluoroethylene (PTFE).

[0026] The internal support may be formed on a part or all of the current collector surface or the side surface of the current collector.

[0027] Additionally, the thickness of the internal support may decrease from the center of the current collector toward the sides.

[0028] The internal support may have at least one support bar formed therein in the width direction and the length direction, the support bar having elastic restoring force.

[0029] Furthermore, the present invention can also be provided in the form of various combinations of means for solving the above problems. [Effects of the Invention]

[0030] As described above, the curved secondary battery according to the present invention can maintain its curved shape even after repeated charge and discharge.

[0031] In addition, the internal support member having elastic restoring force can maintain the curved shape of the secondary battery even in a high temperature environment caused by charging and discharging within the electrode assembly.

[0032] Therefore, it is possible to reinforce weak parts that occur when manufacturing curved cells, thereby preventing curvature deformation. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a conceptual diagram of a curved secondary battery on which an existing reinforcement layer is formed. [Figure 2] FIG. 1 is a perspective view of a curved secondary battery on which an existing reinforcement layer is formed. [Figure 3] 10 is a graph showing a curvature deformation rate and thickness change depending on the number of charge / discharge cycles of a curved secondary battery and a curved secondary battery having a conventional reinforced layer; [Figure 4] 10A and 10B are diagrams showing the shape deformation of a curved secondary battery with an existing reinforced layer formed thereon mounted on a device. [Figure 5] 1 is a cross-sectional view of an electrode assembly having an internal support formed on a current collector surface according to an embodiment of the present invention; [Figure 6] 1 is a cross-sectional view of an electrode assembly in which an internal support is formed on a side of a current collector according to an embodiment of the present invention; [Figure 7] 1 is a cross-sectional view of a curved secondary battery having an internal support formed on a current collector surface according to an embodiment of the present invention; [Figure 8] 1 is a cross-sectional view of a curved secondary battery before disassembly, in which an internal support is formed on a current collector surface according to an embodiment of the present invention; [Figure 9]1 is a cross-sectional view of a curved secondary battery according to an embodiment of the present invention, in which an internal support is formed on a current collector surface, after being disassembled. [Figure 10] 3A and 3B are cross-sectional views of a curved secondary battery having an internal support and an adhesive layer formed on a current collector surface according to an embodiment of the present invention, before and after disassembly. [Figure 11] 1 is a diagram of an electrode assembly including an internal support with varying thickness according to one embodiment of the present invention. [Figure 12] 1 is a perspective view of an electrode assembly including an internal support including a support bar according to one embodiment of the present invention. [Figure 13] 2 is a cross-sectional view taken along line AA' of an electrode assembly including an internal support including a support bar according to an embodiment of the present invention. [Figure 14] 1 is a cross-sectional view taken along line BB' of an electrode assembly including an internal support including a support bar according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person skilled in the art to easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0035] Furthermore, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean that other elements are excluded, but that other elements may also be included.

[0036] Furthermore, descriptions that limit or add specific elements are applicable to all inventions and are not limited to a particular invention unless otherwise specified.

[0037] Furthermore, throughout the description of the present invention and the claims, the singular includes the plural unless otherwise stated.

[0038] Furthermore, throughout the description of the present invention and the claims, unless otherwise specified, "or" includes "and." Therefore, "including A or B" means three cases: including A, including B, or including both A and B.

[0039] The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG.

[0040] The electrode assembly may be fabricated by stacking, for example, a positive electrode plate coated with a positive electrode active material, a negative electrode plate coated with a negative electrode active material, and a separator interposed between the positive and negative electrode plates.

[0041] The electrode assembly may be fabricated by stacking a positive electrode plate, a separator, and a negative electrode plate and winding the stack into a jelly roll.

[0042] The positive electrode plate may include a positive electrode active material portion coated with a positive electrode active material and a positive electrode uncoated portion not coated with the positive electrode active material. The positive electrode active material may be a lithium-containing transition metal oxide or a lithium chalcogenide compound, such as LiCoO2, LiNiO2, LiMnO2, or LiMnO4.

[0043] The positive electrode active material portion may be formed by coating a positive electrode active material on at least a portion of one surface of an aluminum plate, and the remaining portion of the aluminum plate not coated with the positive electrode active material may be a positive electrode uncoated portion.

[0044] The negative electrode plate may include a negative electrode active material portion coated with a negative electrode active material and a negative electrode uncoated portion not coated with the negative electrode active material. The negative electrode active material may be a carbon material such as crystalline carbon, amorphous carbon, a carbon composite, or a carbon fiber, lithium metal, or a lithium alloy.

[0045] The negative electrode active material portion may be formed by coating a negative electrode active material on at least a portion of one surface of a copper plate, and the remaining portion of the copper plate not coated with the negative electrode active material may be a negative electrode uncoated portion.

[0046] The separator can be produced, for example, by coating a substrate made of any one material selected from the group consisting of polyethylene (PE), polystyrene (PS), polypropylene (PP), and a copolymer of polyethylene (PE) and polypropylene (PP) with a polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP copolymer).

[0047] A first electrode tab and a second electrode tab 134 are attached to the electrode assembly. Specifically, the first electrode tab and the second electrode tab 134 are attached to the positive electrode uncoated portion and the negative electrode uncoated portion, respectively, and the first electrode tab and the second electrode tab may be led out through the pouch.

[0048] The pouch seals the electrode assembly and contains the electrolyte inside. For example, the pouch may have a three-layer structure consisting of an insulating layer, a metal layer, and another insulating layer. For example, the metal layer may be made of aluminum, steel, stainless steel, etc., and the insulating layer may be made of modified polypropylene (CPP), polyethylene terephthalate (PET), nylon, etc., but is not limited thereto.

[0049] The pouch may include a pair of wings formed by melt-welding. The pouch may include a receiving portion forming a first surface and a cover portion forming a second surface. The receiving portion has a receiving space capable of receiving an electrode assembly. When the electrode assembly is received in the receiving space, the cover portion, which is formed continuously with the receiving portion on one side, is folded onto the receiving portion, and the receiving portion and the cover portion are melt-welded and joined at the edge of the receiving space. This allows the electrode assembly to be sealed, and the edges where the receiving portion and the cover portion are joined form a pair of wings. The pair of wings may be folded parallel to the curved side surfaces of the secondary battery.

[0050] The curved cell has a curved shape with a certain radius of curvature R due to the molding process. That is, the curved cell can have a certain curved surface depending on the shape of the electronic device to be mounted, thereby eliminating gaps between the electronic device and the curved cell, allowing for efficient use of the internal space of the electronic device and preventing damage to the curved cell due to movement of the curved cell inside the electronic device (not shown).

[0051] However, the smaller the radius of curvature R of the curved cell, the greater the pressure that must be applied to the curved cell during the molding process. This increased pressure can result in areas where stress concentrates in the pressed curved cell, potentially causing deformation, such as distortion, in the curved cell. However, the present invention minimizes the stress generated in the curved cell by applying minimal pressure through two molding processes, enabling the manufacture of curved cells with a small radius of curvature R of 50R or less.

[0052] (Comparative Example)

[0053] FIG. 1 is a conceptual diagram of a curved secondary battery with an existing reinforced layer.

[0054] FIG. 2 is a perspective view of a curved secondary battery having an existing reinforcement layer formed thereon.

[0055] The curved secondary battery may have a curved shape with a certain radius of curvature R. That is, the curved secondary battery has a certain curved surface according to the shape of the electronic device to which it is attached, thereby eliminating the space between the electronic device and the curved secondary battery and efficiently utilizing the internal space of the electronic device.

[0056] The curved secondary battery of Figures 1 and 2 may include an electrode assembly, a pouch having a first exterior material and a second exterior material that seal the electrode assembly, and a reinforcing layer 150 attached onto the first exterior material.

[0057] FIG. 3 is a graph showing the curvature deformation rate and thickness change depending on the number of charge / discharge cycles of a curved secondary battery and a curved secondary battery having a conventional reinforced layer.

[0058] The curvature change rate and thickness change depending on the number of charge / discharge cycles were measured for a curved secondary battery with a reinforcement layer formed on the outside of a conventional pouch and a curved secondary battery without any auxiliary member.

[0059] As can be seen from Figure 3, during the first 100 cycles, there is almost no difference in the curvature change rate between the curved battery with a reinforcing layer and the curved secondary battery without a supporting member, and the curvature change rate increases to 7%.

[0060] It can be seen that after 100 cycles or more, the rate of change in curvature increases slightly up to 10% for the curved secondary battery with the reinforcement layer and the curved secondary battery without the auxiliary member.

[0061] Therefore, it can be confirmed that the reinforcing layer has almost no effect in reducing the curvature change rate of a curved secondary battery.

[0062] From FIG. 3, it can be seen that there is almost no difference in the thickness change rate between the curved battery with a reinforcing layer and the curved secondary battery without a supporting member until the first 100 cycles, and the thickness change increases to 5%.

[0063] It can be seen that after 100 cycles or more, the thickness change increases slightly to 6% for the curved secondary battery with the reinforcement layer and the curved secondary battery without the auxiliary member.

[0064] Therefore, it can be seen that the reinforcing layer has almost no effect in reducing thickness variation in a curved secondary battery.

[0065] FIG. 4 is a diagram showing the shape deformation of a curved secondary battery having an existing reinforced layer mounted on a device.

[0066] When an existing curved secondary battery with a reinforced layer formed on the outside of the pouch is assembled into a device that requires energy, lifting (210) may occur in the curved secondary battery with the reinforced layer after charging and discharging.

[0067] FIG. 5 is a cross-sectional view of an electrode assembly having an internal support formed on a current collector surface according to an embodiment of the present invention.

[0068] The curved secondary battery may include an electrode assembly 100 having a curved positive electrode / separator / negative electrode stacked structure, a cell case 200 that houses the electrode assembly therein, and a curved internal support 300 formed on at least one surface of the electrode assembly.

[0069] The electrode assembly may include a separator between electrode plates, preferably current collectors, on which positive and negative electrode active materials are formed, forming positive and negative electrodes.

[0070] For example, the electrode assembly may include a positive electrode plate, a separator, and a negative electrode plate stacked in order.

[0071] Alternatively, the electrode assemblies may be wound together around a winding shaft to form a jelly-roll structure.

[0072] The electrode assembly may also be bent in a direction perpendicular to the length direction, so that the central axis of the stack may have a curved shape. Thus, the electrode assembly may include a first surface S1 that is curved concavely and a second surface S2 that is curved convexly and is opposite to the first surface S1.

[0073] The electrode assembly may be a stack / folding type electrode assembly in which a stack type mono-cell, bi-cell, or full cell is sequentially wound around a separator sheet as a unit cell.

[0074] The basic unit of the electrochemical cell was a monocell, a full cell, or a bicell.

[0075] A monocell can have a double-sided electrode plate structure in which electrode active material is applied to both sides of a current collector. Since the monocell is a double-sided electrode plate itself, rather than a laminated structure of a separator and an electrode plate, it is easy to handle during processing.

[0076] An electrode assembly with an advanced structure that is a combination of the jelly roll type and stack type may be a full cell with a positive electrode / separator / negative electrode structure of a certain unit size, or a stack / folding type electrode assembly with a bicell with a positive electrode (negative electrode) / separator / negative electrode (positive electrode) / separator / positive electrode (negative electrode) structure folded using a long continuous separator film.

[0077] The characteristics of a full cell or bicell are largely determined by the electrodes, electrolyte, and other materials used. The amount of active material added to the electrode ultimately determines the maximum number of lithium ions that can be bound, so a higher active material content allows for a higher-capacity battery. Therefore, if the binder has excellent adhesive strength and the amount of binder added can be reduced, an electrode can be manufactured that allows for a correspondingly higher active material content. Therefore, there is a need for the invention of a binder with excellent adhesive strength.

[0078] FIG. 6 is a cross-sectional view of an electrode assembly in which an internal support is formed on the side of a current collector according to an embodiment of the present invention.

[0079] In addition, the inner support may be formed on the collector surfaces 110 and 120 of the current collector forming the electrode, on which the active material layer is not formed.

[0080] The current collector surface may be the outermost electrode of an electrode assembly in which a plurality of electrodes are stacked.

[0081] The electrodes may be negative and / or positive.

[0082] In addition, the internal support may be formed on one or more longitudinal (y-direction) current collector sides 130, 140 of the stacked electrode assemblies.

[0083] Therefore, the internal support may contact the sides of the stacked electrodes and separator.

[0084] The internal support may be formed to surround the sides of the stacked electrodes and separator.

[0085] The internal support may be configured to surround the entire side surface of the electrode current collector and a portion of the surface of the electrode current collector.

[0086] The inner support may be U-shaped.

[0087] FIG. 7 is a cross-sectional view of a curved secondary battery having an internal support formed on a current collector surface according to an embodiment of the present invention.

[0088] FIG. 8 is a cross-sectional view before disassembly of a curved secondary battery having an internal support formed on a current collector surface according to an embodiment of the present invention.

[0089] The material of the internal support may be one or more selected from the group consisting of metal, ceramic, and polymer compound.

[0090] The polymer compound may also be a thermosetting polymer compound.

[0091] The thermosetting polymer compound may be one or more selected from the group consisting of polyamide (PA), polyarylene ether (PPE), polyether ether ketone (PEEK), polyimide (PI), and polytetrafluoroethylene (PTFE).

[0092] 9 is a cross-sectional view of a curved secondary battery having an internal support formed on a current collector surface according to an embodiment of the present invention, after disassembly. An adhesive layer 400 may be formed between the internal support and the current collector surface or the side surface of the current collector.

[0093] The adhesive layer 400 may be made of one or more of epoxy, silicone, polyurethane, polyamide, Teflon, and ceramic adhesives.

[0094] FIG. 10 is a cross-sectional view of a curved secondary battery having an internal support and an adhesive layer formed on a current collector surface according to an embodiment of the present invention, before and after disassembly.

[0095] The internal support may be formed on a part or all of the current collector surface or the side surface of the current collector.

[0096] FIG. 11 is a diagram of an electrode assembly including an internal support with varying thickness according to one embodiment of the present invention.

[0097] Additionally, the thickness of the internal support may decrease from the center of the current collector toward the sides.

[0098] FIG. 12 is a diagram of an electrode assembly including an internal support including a support bar according to one embodiment of the present invention.

[0099] In addition, the internal support may have one or more support bars 310 formed therein in the width and length directions, each of which has elastic restoring force.

[0100] This makes it possible to prevent damage to the curved secondary battery due to the curved secondary battery moving freely inside the electronic device.

[0101] FIG. 13 is a cross-sectional view taken along line AA' of an electrode assembly including an internal support including a support bar according to one embodiment of the present invention.

[0102] FIG. 14 is a cross-sectional view taken along line BB' of an electrode assembly including an internal support including a support bar according to one embodiment of the present invention.

[0103] The cross-sectional shape of the support bar 310 may be any one of a circle, a triangle, a square, and an "L" shape.

[0104] One or more support bars 310 may be formed inside the inner support member in contact with the current collector surface or the side surface of the current collector.

[0105] The internal support may have one or more support bars 310 formed therein that have elastic restoring force and have different lengths.

[0106] The internal support may have one or more support bars 310 formed therein that have elastic restoring force and have different thicknesses.

[0107] The material of the support bar 310 may be at least one of metal, polymer, and ceramic components.

[0108] The elastic restoring force of the support bar 310 may be equal to or greater than that of the inner support, and the support bar 310 and the inner support may be made of the same material.

[0109] Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above content. [Explanation of symbols]

[0110] 100 electrode assembly 110, 120 Current collector surface 122 Pouch cup part 124 Pouch cover part 130, 140 Current collector side 132 Electrode tab 200 cell cases 210 Floating occurs 300 Internal support 310 Support bar 400 adhesive layer

Claims

1. an electrode assembly having a curved positive electrode / separator / negative electrode laminated structure; a cell case that accommodates the electrode assembly therein; and a curved internal support formed on at least one surface of the electrode assembly.

2. The curved secondary battery according to claim 1 , wherein the electrode assembly is a stack / folding type electrode assembly in which a stack type mono-cell, bi-cell, or full cell is sequentially wound around a separator sheet as a unit cell.

3. The curved secondary battery according to claim 1 , wherein the internal support is formed on a surface of a current collector that forms an electrode and on which an active material layer is not formed.

4. The curved secondary battery according to claim 1 , wherein the internal support is formed on one or more longitudinal (y-direction) current collector sides of the stacked electrode assemblies.

5. The curved secondary battery according to claim 3 , wherein the material of the internal support is selected from one or more of metal, ceramic, and polymer compound.

6. The curved secondary battery according to claim 5 , wherein the polymer compound is a thermosetting polymer compound.

7. 7. The curved secondary battery according to claim 6, wherein the thermosetting polymer compound is at least one selected from the group consisting of polyamide (PA), polyarylene ether (PPE), polyether ether ketone (PEEK), polyimide (PI), and polytetrafluoroethylene (PTFE).

8. The curved secondary battery according to claim 3 or 4, wherein an adhesive layer is formed between the internal support and the current collector surface or the side surface of the current collector.

9. The curved secondary battery according to claim 8 , wherein the adhesive layer is made of one or more adhesives selected from the group consisting of epoxy, silicone, polyurethane, polyamide, Teflon, and ceramic adhesives.

10. The curved secondary battery according to claim 3 or 4, wherein the internal support is formed on a part or all of the current collector surface or the side surface of the current collector.

11. 5. The curved secondary battery according to claim 3, wherein the thickness of the internal support decreases from the center of the current collector toward the sides.

12. The curved secondary battery according to claim 3 or 4, wherein the internal support has at least one support bar formed therein in the width direction and the length direction, the support bar having elastic restoring force.

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