Rechargeable batteries and battery modules containing them

Abstract

The present invention relates to a secondary battery and a battery module including the same, and more particularly to a secondary battery and a battery module including the same that can relieve or support stress generated in a core portion of an internal jelly-roll-type electrode assembly during charging and discharging of the secondary battery, thereby preventing irreversible electrode deformation occurring in the core portion and collapse of the core portion that may occur due to the accumulation of such deformation.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0121207 filed on September 23, 2022, and Korean Patent Application No. 10-2023-0119979 filed on September 8, 2023, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference in their entirety.

[0002] The present invention relates to a secondary battery and a battery module including the same, and relates to a secondary battery that relieves or supports stress generated in a core portion of an internal jelly-roll type electrode assembly during charging and discharging of the secondary battery, thereby preventing irreversible deformation of the electrodes occurring in the core portion and collapse of the core portion that may occur due to accumulation thereof, and a battery module including the same.

Background Art

[0003] Secondary batteries are classified into cylindrical batteries and prismatic batteries in which an electrode assembly is built into a cylindrical or prismatic metal can depending on the shape of the battery case, and pouch-type batteries in which the electrode assembly is built into a pouch-shaped case made of an aluminum laminate sheet.

[0004] In addition, the electrode assembly built into the battery case is a power generation element capable of charging and discharging, having a laminated structure of a positive electrode / separator / negative electrode, and includes a jelly-roll type structure wound with a separator interposed between a long sheet-shaped positive electrode and a negative electrode coated with an active material, a stack type structure in which a large number of positive electrodes and negative electrodes of a predetermined size are sequentially laminated with a separator interposed therebetween, and a stack / folding type electrode assembly having a structure in which a bicell or full cell in which a positive electrode and a negative electrode of a predetermined unit are laminated with a separator interposed therebetween is wound.

[0005] Among these, jelly roll type electrode assemblies are widely manufactured due to their ease of production and high energy density per unit weight. Jelly roll type electrode assemblies are manufactured by assembling a laminate consisting of long sheet-like positive and negative electrodes with a separator interposed between them, and then winding the laminate in the length direction of the sheet while a winding core is in contact with one end of the electrode laminate. Such a jelly roll type electrode assembly can then be inserted into a battery case made of a cylindrical metal can to form a cylindrical secondary battery.

[0006] With technological advancements, cylindrical secondary batteries are becoming increasingly high-capacity, resulting in a shortage of usable space for battery elements such as electrodes. Therefore, there is a need for a solution that can effectively relieve stress in the core of cylindrical batteries, such as structural collapse within the jelly roll electrode assembly due to the contraction and expansion of electrodes.

[0007] Figure 1 is a cross-sectional view showing an example of a conventional cylindrical secondary battery. Referring to Figure 1, the cylindrical secondary battery includes a jelly roll type electrode assembly 10 formed by alternately stacking and winding electrodes and separators, and a can case 20 that houses the jelly roll type electrode assembly. A core portion 11 is formed in the winding center of the jelly roll type electrode assembly 10. The core portion 11 is an empty space formed by removing the winding core after the jelly roll type electrode assembly 10 has been manufactured by winding the stack of electrodes and separators on the winding core.

[0008] Figure 2 is a cross-sectional view along line A-A' in Figure 1. Referring to Figure 2, Figure 2(a) shows the initial state of the core portion 11 of the jelly roll type electrode assembly 10 before it collapses. When charging and discharging occur in the state shown in Figure 2(a), the electrode assembly 10 (jelly roll type electrode assembly 10) and the core portion 11 of the electrode assembly 10 repeatedly expand and contract. This causes the electrodes of the core portion 11 to deform or collapse due to the accumulation of deformation, and Figure 2(b) shows this state of deformation and collapse of the core portion 11.

[0009] If deformation or collapse occurs inside the core portion 11 of the electrode assembly 10, there is a risk of internal short circuits leading to micro-shorts or explosions, such as when the separator is torn by the corners of the electrodes, which poses a problem. [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to provide a secondary battery and a battery module including the same that can relieve or support stress generated in the core portion of the internal jelly roll type electrode assembly during charging and discharging of the secondary battery, thereby preventing irreversible electrode deformation occurring in the core portion and the collapse of the core portion that may occur due to the accumulation of these deformations.

[0011] Furthermore, the present invention aims to provide a secondary battery and a battery module including the same, which prevent the problem of smooth winding of a jelly roll-type electrode assembly with a small core diameter due to the rigidity of the core of the electrode assembly when winding it. [Means for solving the problem]

[0012] The secondary battery according to the present invention includes a jelly roll type electrode assembly formed by winding a positive electrode, a negative electrode, and a separator; a case for housing the electrode assembly; and an electrolyte solution housed in the case together with the electrode assembly. A swelling tape that expands when it absorbs the electrolyte solution is attached to one surface of the separator, which is located so as to surround the core portion that is the winding center of the electrode assembly. The swelling tape includes a base material and an adhesive layer formed on one of the two surfaces of the base material that faces the separator. The base material includes a plurality of protruding portions formed on the side opposite to the surface on which the adhesive layer is formed.

[0013] The base material may include polymer materials.

[0014] One side of the separator can be the side of the separator that faces the core.

[0015] The electrode assembly has a configuration in which a first separator, a positive electrode, a second separator, and a negative electrode are stacked in order and wound up, and the sweeping tape can be attached to the first separator.

[0016] The sweeping tape can be attached to the separator such that the core-side end of the separator and the core-side end of the sweeping tape coincide with each other.

[0017] The protrusion can be formed in a shape that narrows in width from the bottom to the top, based on a cross-sectional view obtained by cutting the electrode assembly with a plane perpendicular to the winding shaft.

[0018] The protrusions are formed to extend in the width direction of the separator, and multiple protrusions can be arranged so that they are spaced apart above adjacent protrusions in the length direction of the separator, and touch below.

[0019] The protrusion can be formed in the shape of a semicircle or a part of a circle, based on a cross-sectional view obtained by cutting the electrode assembly with a plane perpendicular to the winding shaft.

[0020] The protrusion can be formed in a trapezoidal shape based on a cross-sectional view obtained by cutting the electrode assembly with a plane perpendicular to the winding shaft.

[0021] A trapezoid can be an isosceles trapezoid.

[0022] The core diameter (P) can be formed to 3.2 mm to 3.6 mm, and the substrate thickness (t) can be formed to 30 μm to 50 μm.

[0023] The length (U) of the lower side of the trapezoidal protrusion is 0.1 mm to 0.3 mm, and the angle (θ) of the protrusion, which is the angle formed by the intersection of two straight lines created by extending a pair of non-parallel sides in the trapezoidal shape, can be 6.5 degrees to 7.9 degrees.

[0024] The length (U) of the lower side of the convex portion having a trapezoidal shape is 0.4 mm to 0.6 mm, and in the trapezoidal shape, the angle (θ) of the convex portion, which is the angle formed by the intersection of two straight lines formed by extending a pair of two non-parallel opposite sides, can be 16 degrees to 20 degrees.

[0025] The battery module according to the present invention includes the secondary battery according to the present invention described above and a housing in which a plurality of the secondary batteries are accommodated.

Effect of the Invention

[0026] The secondary battery and the battery module including the same according to the present invention can eliminate or support the stress generated in the core portion of the internal jelly-roll type electrode assembly during charging and discharging of the secondary battery, thereby preventing irreversible electrode deformation in the core portion and collapse of the core portion that may occur due to the accumulation thereof.

[0027] In addition, the secondary battery and the battery module including the same according to the present invention can prevent a problem that the core portion of the electrode assembly is not smoothly wound due to the rigidity of the core portion of the electrode assembly when winding a jelly-roll type electrode assembly having a small core diameter.

Brief Description of the Drawings

[0028] [Figure 1] It is a cross-sectional view showing an example of a conventional cylindrical secondary battery. [Figure 2] It is a cross-sectional view taken along the line A-A' of FIG. 1. [Figure 3] It is a cross-sectional view of the secondary battery according to Embodiment 1 of the present invention cut in the same manner as A-A' of FIG. 1. [Figure 4] It is a perspective view showing a state in which the jelly-roll type electrode assembly of the secondary battery according to Embodiment 1 of the present invention is developed and disassembled. [Figure 5] It is a perspective view showing an enlarged view of the B portion of FIG. 4. [Figure 6] It is a side view showing the shape viewed from the direction of arrow E in FIG. 5. [Figure 7] This is a side view showing the state in which the jelly roll type electrode assembly is being wound up using a winding core in a secondary battery according to Embodiment 1 of the present invention. [Figure 8] This is a side view showing another modification of the embodiment shown in Figure 7. [Figure 9] This is a side view showing a secondary battery according to Embodiment 2 of the present invention, with a swelling tape attached. [Figure 10] This is a side view showing a secondary battery according to Embodiment 3 of the present invention with a swelling tape attached. [Modes for carrying out the invention]

[0029] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be realized in a variety of different forms and is not limited to or restricted to the following embodiments.

[0030] To clearly illustrate the present invention, detailed descriptions of relevant prior art that are not relevant to the description or that may obscure the gist of the invention have been omitted. In this specification, when assigning reference numerals to components in each drawing, the same or similar reference numerals are used throughout the specification for components that are the same or similar.

[0031] Furthermore, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary and dictionary meanings, but rather should be interpreted in a manner and concept consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0032] Embodiment 1 Figure 1 is a cross-sectional view showing an example of a conventional cylindrical secondary battery. Figure 2 is a cross-sectional view taken along line A-A' in Figure 1. Figure 3 is a cross-sectional view of a secondary battery according to Embodiment 1 of the present invention, taken in the same manner as line A-A' in Figure 1. Figure 4 is a perspective view showing the jelly roll electrode assembly of the secondary battery according to Embodiment 1 of the present invention unfolded and disassembled. Figure 5 is a perspective view showing an enlarged view of part B in Figure 4. Figure 6 is a side view showing the shape as seen from the direction of arrow E in Figure 5. Figure 7 is a side view showing the state in which the jelly roll electrode assembly is started to be wound using a winding core in the secondary battery according to Embodiment 1 of the present invention.

[0033] Referring to Figures 3, 4, and 7, the secondary battery 100 according to Embodiment 1 of the present invention includes an electrode assembly 110, a case, and an electrolyte, and a sweeping tape 130 is attached to the core portion 120, which is the central part of the electrode assembly 110.

[0034] The electrode assembly 110 can be a jelly roll type electrode assembly 110 formed by alternately stacking and winding a negative electrode 112, a positive electrode 114, and a separator 115. The case can be a case for housing the electrode assembly. The case can be a cylindrical can case. The electrolyte (not shown) can be a liquid housed in the case together with the electrode assembly 110.

[0035] Furthermore, a core portion 120 is formed in the winding center of the jelly roll type electrode assembly 110. The core portion 120 can be an empty space formed by winding the laminate of electrodes and separators 115 on a winding core K to produce the jelly roll type electrode assembly 110, and then removing the winding core K.

[0036] In the secondary battery according to Embodiment 1 of the present invention, a sweeping tape 130 is attached to one surface of a separator 115 that is positioned to surround the core portion 120, which is the winding center of the electrode assembly 110. In this case, the one surface of the separator 115 can be the surface of the separator 115 that faces the core portion 120.

[0037] Specifically, referring to Figures 4 and 7, the electrode assembly 110 can be provided in a form in which the first separator 111, the negative electrode 112, the second separator 113, and the positive electrode 114 are stacked and wound in that order. The sweeping tape 130 can be attached to the second separator 113 of the two separators 115 mentioned above. This means that it is attached to the separator 115 inside the core. When attached to the separator 115 on the inside of the core, it does not affect the battery reaction because it is at a distance from the opposing surface between the positive and negative electrodes, thus eliminating the problem of changes in battery characteristics. Furthermore, in the battery manufacturing process, the sweeping tape 130 plays a supporting role when the core K is taken and wound in the winding direction (W), which is more advantageous (see Figure 7). Here, the core K refers to two rods that take the center of the separator 115 for the winding process. After the core K rotates and forms the jelly roll type electrode assembly 110 through the winding process, the core K is removed.

[0038] Figure 8 is a side view showing another modification of the embodiment shown in Figure 7. Referring to Figure 8, as another modification of the electrode assembly, the electrode assembly 110 may be provided in a form in which a first separator 111, a positive electrode 114, a second separator 113, and a negative electrode 112 are stacked and wound in order. The sweeping tape 130 may similarly be attached to the second separator 113 of the two separators 115. This is similarly attached to the separator 115 inside the core.

[0039] Referring to Figures 4 and 5, the sweeping tape 130 can be attached to the separator 115 such that the core-side end of the separator 115 to which the sweeping tape 130 is attached coincides with the core-side end of the sweeping tape 130 (specifically, the sweeping tape 130 can be attached so that it coincides with the core-side end of the second separator 113). The core side is indicated by the arrow in direction O in Figure 4. The core side may mean the direction toward the winding center.

[0040] The swelling tape 130 can be a tape that expands when it absorbs an electrolyte. For example, the swelling tape 130 can include a polymer material. The polymer material can be a material that absorbs an electrolyte but does not react with the electrolyte. Specifically, it can include a PU (polyurethane) material.

[0041] Specifically, the sweeping tape 130 may include a base material 131 and an adhesive layer 132. The adhesive layer 132 may be an adhesive material layer applied to one surface of the base material 131. More specifically, the base material 131 of the sweeping tape 130 may be formed to include a polymer material. More specifically, the base material 131 may include a PU (polyurethane) material. Other materials can be used as the base material 131, as long as they are materials that can absorb an electrolyte and expand. The expanded base material 131 can buffer or absorb shocks and stresses. Alternatively, it can play a role in supporting while resisting shocks and stresses. The adhesive layer 132 may be formed on one of the two surfaces of the base material 131, the surface facing the separator 115.

[0042] Referring to Figures 5 and 6, in the secondary battery according to Embodiment 1 of the present invention, a plurality of recesses 134 and protrusions 133 can be formed on the substrate 131. Specifically, the protrusions 133 can be formed on the side opposite to the surface on which the adhesive layer 132 is formed. The recesses 134 can have a concave shape. The protrusions 133 can have a shape that is relatively higher and thicker than the recesses.

[0043] For reference, the recessed portion 134 and the protruding portion 133 can be manufactured by laser etching using a method that involves irradiating a tape with a laser. Alternatively, they may be manufactured by a method that involves applying pressure using a mold.

[0044] In the secondary battery according to Embodiment 1 of the present invention, by attaching a swelling tape 130 to the separator 115 located in the core portion 120, stress generated in the core portion 120 of the internal jelly roll type electrode assembly 110 during charging and discharging of the secondary battery can be relieved or supported. This prevents irreversible electrode deformation occurring in the core portion 120 and the collapse of the core portion 120 that may occur due to the accumulation of these deformations.

[0045] Referring to Figure 3, Figure 3(a) shows the shape of the core portion 120 before expansion and contraction occur, before the electrolyte is injected, and Figure 3(b) shows the shape of the core portion 120 after expansion and contraction occur, after the electrolyte is injected. Referring to Figure 3(b), it can be seen that, due to the swollen swelling tape 130, the core portion 120 maintains its shape without deforming or collapsing even after repeated expansion and contraction of the core portion 120.

[0046] Figure 6 is a side view showing the shape as seen from the direction of arrow E in Figure 5. Referring to Figure 6, the protrusion 133 can be formed in a shape that narrows in width from the bottom to the top, based on a cross-sectional view taken with a plane perpendicular to the winding shaft of the electrode assembly 110. Referring to Figure 5, the protrusion 133 can be formed to extend in the width direction (Y) of the separator 115 (113). As shown in Figure 4, the width of the sweeping tape 130 can also be the same as the width of the separator 115. Referring to Figure 6, the length (J) of the sweeping tape 130 can be formed so that it is neither too long nor too short, based on the length direction (L) of the separator 115. Specifically, the length (J) of the sweeping tape 130 can be determined within a range that does not interfere with the battery reaction.

[0047] Furthermore, referring to Figures 5 and 6, the multiple protrusions 133 can be arranged such that they are spaced apart on the upper side and touching on the lower side of adjacent protrusions 133 in the longitudinal direction (L) of the separator 115.

[0048] Referring to Figure 6, specifically, the protrusion 133 can be formed in a trapezoidal shape based on a cross-sectional view obtained by cutting the electrode assembly 110 with a plane perpendicular to the winding shaft. Here, an isosceles trapezoid is particularly preferred as the trapezoid.

[0049] By forming the shape of the protrusion 133 in this manner, when winding up a jelly roll-type electrode assembly 110 with a small diameter core portion 120, the rigidity of the sweeping tape 130 attached to the core portion 120 of the electrode assembly 110 prevents the assembly from being wound up smoothly.

[0050] Specifically, the sweeping tape 130 needs to have a certain degree of rigidity to prevent the core portion 120 from collapsing, but such rigidity may make it difficult for the core portion 120 to form a winding. This is because the rigidity of the sweeping tape 130 may act as a force that causes the winding to unravel.

[0051] Furthermore, when the electrolyte solution is injected after the insertion of the jelly roll-type electrode assembly 110, the volume of the swelling tape 130 expands. This expansion of the swelling tape 130 can sometimes exert a force in the direction of unwinding. The protrusion 133 of the present invention can play a role in solving the problem of such unwinding and the failure to form smoothly.

[0052] Specifically, the space between the protrusions 133 plays a role in weakening the rigidity or repulsive force of the sweeping tape 130, thereby solving the problems of the sweeping tape 130 unwinding due to its rigidity or not forming smoothly.

[0053] Referring to Figures 3 and 6, in the secondary battery according to Embodiment 1 of the present invention, the diameter (P) of the core portion 120 can be formed to 3.2 mm to 3.6 mm, and the thickness (t) of the substrate 131 can be formed to 30 μm to 50 μm (in micrometers). Furthermore, the thickness of the substrate layer excluding the protrusions can be formed to be about 1 / 4 to 1 / 3 of the total substrate layer thickness. This is the most advantageous thickness range in which the adhesive layer is not exposed and protrusions are formed.

[0054] Furthermore, the length (U) of the lower side of the trapezoidal protrusion 133 can be 0.1 mm to 0.3 mm. In this case, the angle (θ) of the protrusion 133, which is the angle formed by the intersection of two straight lines that are formed by extending a pair of opposite sides that are not parallel in the trapezoidal shape, can be 6.5 degrees to 7.9 degrees.

[0055] For reference, the calculation method is as follows: When the diameter (P) of the core part 120 is approximately 3.2 mm, the circumference of the core part 120 is 3.2 mm × 3.14 (pi) = approximately 10 mm. Assuming that the length (U) of the lower side of the protrusion 133 is approximately 0.2 mm, dividing the above 10 mm by 0.2 mm allows approximately 50 protrusions 133 to be formed around the core part 120. Therefore, dividing 360 degrees by 50 gives an angle of approximately 7.2 degrees for the protrusion 133. Applying a tolerance range of approximately 10%, we get 7.2 - 0.7 = 6.5 degrees, and 7.2 + 0.7 = 7.9 degrees.

[0056] Furthermore, the length (U) of the lower side of the trapezoidal protrusion 133 can be 0.4 mm to 0.6 mm. In this case, the angle (θ) of the protrusion 133, which is the angle formed by the intersection of two straight lines that are formed by extending a pair of opposite sides that are not parallel in the trapezoidal shape, can be 16 degrees to 20 degrees.

[0057] The same calculation can be performed in this case as well. When the diameter (P) of the core part 120 is approximately 3.2 mm, the circumference of the core part 120 is 3.2 mm × 3.14 (pi) = approximately 10 mm. Assuming that the length (U) of the lower side of the protrusion 133 is approximately 0.5 mm, dividing the above 10 mm by 0.5 mm allows approximately 20 protrusions 133 to be formed around the core part 120. Therefore, dividing 360 degrees by 20 gives an angle of approximately 18 degrees for the protrusion 133. In this case, applying a tolerance range of approximately 10%, we get 18 - 2 = 16 degrees, and 18 + 2 = 20 degrees.

[0058] Furthermore, the battery module according to the present invention may be formed to include a secondary battery according to Embodiment 1 of the present invention described above, and a housing that accommodates a plurality of such secondary batteries.

[0059] Embodiment 2 Figure 9 is a side view showing the state in which the sweeping tape 230 is attached to the secondary battery according to Embodiment 2 of the present invention.

[0060] Embodiment 2 of the present invention differs from Embodiment 1 in that the shape of the protrusion is formed as a circle rather than a trapezoid.

[0061] We will omit as much of the content common to Embodiment 1 as possible and describe Embodiment 2 focusing on the differences. In other words, it is clear that the content not described in Embodiment 2 can be supplemented by the content of Embodiment 1 as needed.

[0062] Referring to Figure 9, in the secondary battery according to Embodiment 2 of the present invention, the protrusion 233 can be formed in the shape of a semicircle or part of a circle, based on a cross-sectional view obtained by cutting the electrode assembly with a plane perpendicular to the winding shaft.

[0063] Figure 9 shows that a semicircular protrusion 233 is formed on the substrate. The substrate 231 on which the semicircular protrusion 233 is formed is attached to one surface of the separator 215, similar to Embodiment 1, and an adhesive layer 232 is formed on one surface of the substrate 231 so that it can adhere to the separator 215.

[0064] When the convex portion is formed in this way, it differs from a trapezoid in that it allows for the absence or reduction of corners.

[0065] Embodiment 3 Figure 10 is a side view showing a secondary battery according to Embodiment 3 of the present invention with a swelling tape attached.

[0066] Compared to embodiments 1 and 2 of the present invention, this invention differs from embodiments 1 and 2 in that it achieves the objective of the present invention by attaching multiple narrow-width sweeping tapes.

[0067] This explanation will focus on the differences between Embodiment 3 and Embodiments 1 and 2, omitting as much common information as possible. In other words, it is clear that any information not described in Embodiment 3 can be supplemented by the information in Embodiments 1 and 2 as needed.

[0068] Referring to Figure 10, the secondary battery according to Embodiment 3 of the present invention includes a jelly roll type electrode assembly 110 formed by winding a negative electrode, a positive electrode, and a separator, a case for housing the electrode assembly, and an electrolyte solution housed in the case together with the electrode assembly 110. Multiple swelling tapes 330, which expand when they absorb the electrolyte solution, can be attached at predetermined intervals to one surface of the separator 315, which is located so as to surround the core portion, which is the winding center of the electrode assembly 110. Each swelling tape 330 may include a base material 331 and an adhesive layer 332 formed on the surface of the base material facing the separator.

[0069] In other words, the present invention is characterized in that each individual sweeping tape 330 has a narrow width and is attached in multiple pieces. In Embodiment 3, one sweeping tape 330 can perform the role that one protrusion 133, 233 performs in Embodiments 1 and 2.

[0070] When formed in this manner, there is no need to use methods such as laser etching to create recesses and protrusions, thus achieving manufacturing convenience. In other words, high-precision or expensive equipment such as separate laser etching equipment is not required, and since it is only necessary to attach multiple sweeping tapes 330, it can be manufactured and used more easily.

[0071] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible by persons with ordinary skill in the art to which the present invention pertains, within an equivalent scope of the technical concept and the appended claims. [Explanation of Symbols]

[0072] 100 Secondary battery 110 Electrode assembly 111 First Separator 112 Negative electrode 113 Second Separator 114 Positive electrode 115, 215, 315 Separators 120 Core section 130, 230, 330 Sweeping Tape 131, 231, 331 base material 132, 232, 332 Adhesive layer 133, 233 protrusions 134, 234 recesses K core W Winding direction

Claims

1. A jelly roll type electrode assembly is formed by winding together a positive electrode, a negative electrode, and a separator, A case for housing the aforementioned jelly roll-type electrode assembly, The case contains an electrolyte solution housed together with the jelly roll-type electrode assembly, A swelling tape that expands when it absorbs the electrolyte is attached to one surface of the separator, which is located so as to surround the core portion that is the winding center of the jelly roll type electrode assembly. The aforementioned sweeping tape is Substrate and The substrate includes an adhesive layer formed on one of its two surfaces that faces the separator, The substrate includes a plurality of recesses and protrusions formed on the side opposite to the surface on which the adhesive layer is formed, The aforementioned protrusion is formed in such a shape that its width narrows from the bottom to the top, based on a cross-sectional view obtained by cutting the jelly roll-type electrode assembly with a plane perpendicular to the winding shaft. The aforementioned protrusion is formed in a trapezoidal shape, based on a cross-sectional view obtained by cutting the jelly roll-type electrode assembly with a plane perpendicular to the winding shaft. The diameter of the core portion is formed to be 3.2 mm to 3.6 mm. The thickness of the aforementioned substrate is formed to be 30 μm to 50 μm. The length of the lower side of the trapezoidal protrusion is 0.1 mm to 0.3 mm. A secondary battery in the trapezoidal shape described above, wherein the angle of the convex portion, which is the angle formed by the intersection of two straight lines that are formed by extending a pair of opposite sides that are not parallel, is between 6.5 degrees and 7.9 degrees.

2. A jelly roll type electrode assembly formed by winding a positive electrode, a negative electrode, and a separator, A case for housing the aforementioned jelly roll-type electrode assembly, The case contains an electrolyte solution housed together with the jelly roll-type electrode assembly, A swelling tape that expands when it absorbs the electrolyte is attached to one surface of the separator, which is located so as to surround the core portion that is the winding center of the jelly roll type electrode assembly. The aforementioned sweeping tape is Substrate and The substrate includes an adhesive layer formed on one of its two surfaces that faces the separator, The substrate includes a plurality of recesses and protrusions formed on the side opposite to the surface on which the adhesive layer is formed, The aforementioned protrusion is formed in such a shape that its width narrows from the bottom to the top, based on a cross-sectional view obtained by cutting the jelly roll-type electrode assembly with a plane perpendicular to the winding shaft. The aforementioned protrusion is formed in a trapezoidal shape, based on a cross-sectional view obtained by cutting the jelly roll-type electrode assembly with a plane perpendicular to the winding shaft. The diameter of the core portion is formed to be 3.2 mm to 3.6 mm. The thickness of the aforementioned substrate is formed to be 30 μm to 50 μm. The length of the lower side of the trapezoidal protrusion is 0.4 mm to 0.6 mm. A secondary battery in the trapezoidal shape described above, wherein the angle of the convex portion, which is the angle formed by the intersection of two straight lines that are extended by a pair of opposite sides that are not parallel, is between 16 and 20 degrees.

3. A jelly roll type electrode assembly formed by winding a positive electrode, a negative electrode, and a separator, A case for housing the aforementioned jelly roll-type electrode assembly, The case contains an electrolyte solution housed together with the jelly roll-type electrode assembly, A swelling tape that expands when it absorbs the electrolyte is attached to one surface of the separator, which is located so as to surround the core portion that is the winding center of the jelly roll type electrode assembly. The aforementioned sweeping tape is Substrate and The substrate includes an adhesive layer formed on one of its two surfaces that faces the separator, The substrate includes a plurality of recesses and protrusions formed on the side opposite to the surface on which the adhesive layer is formed, and is a secondary battery.

4. The secondary battery according to any one of claims 1 to 3, wherein the substrate includes a polymer material.

5. The secondary battery according to any one of claims 1 to 3, wherein one surface of the separator is the surface of the separator that faces the core portion.

6. The jelly roll type electrode assembly has a configuration in which a first separator, a negative electrode, a second separator, and a positive electrode are stacked and wound in that order. The secondary battery according to claim 5, wherein the sweeping tape is attached to the second separator.

7. The jelly roll type electrode assembly has a configuration in which a first separator, a positive electrode, a second separator, and a negative electrode are stacked and wound in that order. The secondary battery according to claim 5, wherein the sweeping tape is attached to the second separator.

8. The secondary battery according to any one of claims 1 to 3, wherein the sweeping tape is attached to the separator such that the core-side end of the separator and the core-side end of the sweeping tape coincide with each other.

9. The secondary battery according to claim 3, wherein the protrusion is formed in a shape that becomes narrower from the bottom to the top, based on a cross-sectional view obtained by cutting the jelly roll-type electrode assembly with a plane perpendicular to the winding shaft.

10. The aforementioned protrusion is formed in a shape that extends in the width direction of the separator, The secondary battery according to any one of claims 1, 2, and 9, wherein the plurality of protrusions are arranged such that they are spaced apart above and in contact below with adjacent protrusions in the longitudinal direction of the separator.

11. The secondary battery according to claim 9, wherein the protrusion is formed in the shape of a semicircle or part of a circle, based on a cross-sectional view obtained by cutting the jelly roll-type electrode assembly with a plane perpendicular to the winding shaft.

12. The secondary battery according to claim 9, wherein the protrusion is formed in a trapezoidal shape based on a cross-sectional view obtained by cutting the jelly roll-type electrode assembly with a plane perpendicular to the winding shaft.

13. The secondary battery according to any one of claims 1, 2, and 12, wherein the trapezoid is an isosceles trapezoid.

14. The diameter of the core portion is formed to be 3.2 mm to 3.6 mm. The secondary battery according to claim 12, wherein the thickness of the substrate is formed to be 30 μm to 50 μm.

15. A jelly roll-type electrode assembly is formed by winding together a negative electrode, a positive electrode, and a separator, A case for housing the aforementioned jelly roll-type electrode assembly, The case contains an electrolyte solution housed together with the jelly roll-type electrode assembly, On one surface of the separator, which is located around the core portion that is the winding center of the jelly roll type electrode assembly, multiple swelling tapes that expand when they absorb electrolyte are attached at predetermined intervals. Each of the aforementioned plurality of sweeping tapes is Substrate and A secondary battery comprising: an adhesive layer formed on one of the two surfaces of the substrate that faces the separator.

16. A secondary battery according to any one of claims 1, 2, 3, and 15, A battery module including a housing that accommodates a plurality of the aforementioned secondary batteries.

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