Electrode assembly and rechargeable battery including the same

Abstract

An electrode assembly and a rechargeable battery including the same are provided. The electrode assembly includes: a first electrode including a first substrate and first active material layers respectively formed on a front surface and a back surface of the first substrate; a second electrode including a second substrate and second active material layers formed on a front surface and a back surface of the second substrate, respectively; a separator between the first electrode and the second electrode; and a first insulating layer and a second insulating layer formed on the front surface and the back surface of the first substrate, respectively, and covering an end portion of the first active material layer, the first insulating layer and the second insulating layer having different lengths.

Description

Technical Field

[0001] Aspects of the present disclosure relate to an electrode assembly and a rechargeable battery including the electrode assembly. Background Art

[0002] With the advancement of technology and the increasing demand for mobile devices, the demand for rechargeable batteries as an energy source is also increasing.

[0003] Among rechargeable batteries, a cylindrical rechargeable battery includes an electrode assembly formed by winding electrodes disposed on both sides of a separator together with the separator into a core shape, a center pin disposed in a hollow portion at the center of the electrode assembly, a case that houses the electrode assembly therein, and a cap assembly that closes and seals an open side of the case.

[0004] In such a rechargeable battery, swelling, deformation, or expansion of the negative electrode active material layer may occur during charging and discharging. At this time, electrodes of different polarities may come into contact with each other and a short circuit may occur.

[0005] In particular, in the case of a cylindrical rechargeable battery, an uncoated electrode portion of the electrode assembly is electrically connected to a current collector in a folded state. In this case, an end portion of an uncoated electrode portion of the other polarity may be placed to face the folded uncoated electrode portion.

[0006] For example, when the negative electrode active material layer expands, the uncoated electrode portion of the negative electrode may come into contact with the folded uncoated electrode portion of the positive electrode, resulting in a short circuit.

[0007] The above information disclosed in this background art section is only for enhancing the understanding of the background of the invention, and thus it may include information that does not constitute the prior art. Summary of the Invention

[0008] Accordingly, aspects of the present disclosure relate to an electrode assembly and a rechargeable battery that can prevent a short circuit from occurring by contacting an uncoated electrode portion of the positive electrode even when the negative active material layer expands.

[0009] According to some embodiments, there is provided an electrode assembly including: a first electrode including a first substrate and first active material layers respectively formed on front and back surfaces of the first substrate; a second electrode including a second substrate and second active material layers respectively formed on front and back surfaces of the second substrate; a separator disposed between the first electrode and the second electrode; and first and second insulating layers respectively formed on the front and back surfaces of the first substrate and covering ends of the first active material layers, the first and second insulating layers having different lengths.

[0010] In some embodiments, one end of the first substrate, on which a first insulating layer and a second insulating layer are formed, is bent toward the center of the electrode assembly.

[0011] In some embodiments, the length of the first insulating layer on the front surface of the first substrate is shorter than the length of the second insulating layer on the back surface of the first substrate and positioned closer to the center of the electrode assembly than the first insulating layer.

[0012] In some embodiments, the length of the second insulating layer is from 5.5 mm to 5.9 mm, and the length of the first insulating layer is from 2.5 mm to 2.7 mm.

[0013] In some embodiments, the first insulating layer and the second insulating layer are not formed on a portion of the first substrate, such that the first substrate further includes a front exposed portion and a back exposed portion that expose the front and back of the first substrate, the width of the front exposed portion is greater than 4.25 mm, and the width of the back exposed portion is greater than 1 mm.

[0014] In some embodiments, the back exposed portion is in direct contact with the front exposed portion of the next turn of the first substrate to be electrically connected to the front exposed portion of the next turn of the first substrate.

[0015] In some embodiments, the second insulating layer faces the end of the second electrode and is spaced apart from the end of the second electrode.

[0016] In some embodiments, the first insulating layer and the second insulating layer are formed of ceramic.

[0017] In some embodiments, the ceramic includes Al 2 O 3 .

[0018] In some embodiments, the thicknesses of the first insulating layer and the second insulating layer are less than 10 μm.

[0019] In some embodiments, the first electrode is a positive electrode and the second electrode is a negative electrode.

[0020] In some embodiments, the thicknesses of the first insulating layer and the second insulating layer are larger than the protruding size of the burr formed on the cut surface of the first electrode.

[0021] In some embodiments, the thicknesses of the first insulating layer and the second insulating layer are greater than 20 μm.

[0022] In some embodiments, the first insulating layer and the second insulating layer overlap the end of the first active material layer with a width of 1 mm or less.

[0023] According to some embodiments, a rechargeable battery is provided, which includes: the above-mentioned electrode assembly; a cylindrical housing configured to accommodate the electrode assembly; a center pin located at the center of the electrode assembly; a cap assembly covering and sealing the cylindrical housing; and an electrolyte accommodated in the cylindrical housing together with the electrode assembly.

[0024] Other aspects, features, and characteristics not described above will be more clearly understood through the drawings, claims, and detailed description. Description of the Drawings

[0025] The accompanying drawings of this specification illustrate some embodiments of the present disclosure and further describe the aspects and features of the present disclosure together with the detailed description of the present disclosure. However, the present disclosure should not be construed as being limited to the drawings.

[0026] Figure 1 is a perspective view showing the internal structure of a rechargeable battery according to some embodiments of the present disclosure.

[0027] Figure 2 is a cross-sectional view showing a part of the electrode assembly in Figure 1 according to some embodiments of the present disclosure.

[0028] Figure 3 is a cross-sectional view showing a part of the electrode assembly in Figure 1 according to some other embodiments of the present disclosure.

[0029] Figure 4 is a cross-sectional view showing the operating effect of preventing short circuit during charge and discharge cycles according to some embodiments of the present disclosure. Detailed Description of the Embodiments

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The terms and words used in this specification and claims will not be construed as having a general meaning or a dictionary meaning, but will be interpreted as having a meaning and concept consistent with the technical concept of the present disclosure based on the principle that the inventors can appropriately define the terms of the present disclosure in order to best describe their disclosure. Therefore, the configurations described in the embodiments and drawings of the present disclosure are only the most preferred embodiments, but do not represent all the technical spirits of the present disclosure. Therefore, the present disclosure should be construed as including all changes, equivalents, and alternatives included in the spirit and scope of the present disclosure at the time of filing this application.

[0031] It should also be understood that when the terms "comprise", "include", and / or their variants are used in this specification, it indicates the presence of the stated features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups thereof.

[0032] In addition, the sizes of some components in the drawings may be exaggerated and not drawn to scale for ease of understanding the present disclosure. Additionally, in another embodiment, the same reference numerals may be assigned to the same components.

[0033] As used herein, the term "and / or" includes any combination and all combinations of one or more of the related listed items. For example, the expression "A and / or B" means A, B, or A and B. Expressions such as "one or more of..." and "at least one of..." when following a list of elements modify the entire list of elements and not individual elements in the list. For example, the expressions "one or more of A, B, and C", "at least one of A, B, or C", "at least one of A, B, and C", and "at least one selected from the group consisting of A, B, and C" mean only A, only B, only C, both A and B, both A and C, both B and C, or all of A, B, and C.

[0034] In addition, when describing embodiments of the inventive concept, the use of "may" refers to "one or more embodiments of the inventive concept". Further, the term "exemplary" is intended to indicate an example or illustration.

[0035] Although terms such as "first", "second", etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another component, but are not limited thereto. Within the technical spirit of the present disclosure, the first component described below may be the second component.

[0036] Throughout the specification, unless otherwise specified, each component may be singular or plural.

[0037] As shown in the drawings, for ease of explanation, spatial relative terms such as "beneath", "below", "under", "underneath", "above", and "on" may be used herein to describe the relationship of one element or feature to another (other) element or feature as shown in the drawings. It should be understood that, in addition to the orientation depicted in the drawings, spatial relative positions are intended to also cover different orientations of the device during use or operation. For example, if the device in the drawing is flipped, an element described as "beneath", "below", or "underneath" other elements or features will then be oriented "above" the said other elements or features. Thus, the term "under" can include both the upper and lower orientations.

[0038] In addition, if a component is described as being "on", "connected to", or "coupled to" another component, these components can be directly connected or connected to each other, but it should be understood that other components can be "between" the respective components, or the respective components can be "connected" or "coupled" through other components.

[0039] The terms used herein are intended to describe embodiments of the present disclosure and are not intended to limit it.

[0040] Figure 1 is a cross-sectional view of a rechargeable battery according to some embodiments of the present disclosure. Figure 2 is a cross-sectional view showing a part of an electrode assembly in Figure 1 according to some embodiments of the present disclosure. Figure 3 is a cross-sectional view showing a part of an electrode assembly in Figure 1 according to some other embodiments of the present disclosure. Figure 4 is a cross-sectional view showing the operating effect of preventing short circuit during charge and discharge cycles according to some embodiments of the present disclosure.

[0041] As Figure 1 shown, a rechargeable battery according to some embodiments includes an electrode assembly 10, a housing 20 for accommodating the electrode assembly 10, a lid assembly 30 bonded to an opening of the housing 20 via a gasket and electrically connected to the electrode assembly 10, an insulating plate 50 disposed between the lid assembly 30 and the electrode assembly 10, and a center pin 60 placed at the center of the electrode assembly 10.

[0042] The electrode assembly 10 includes a first electrode 11, a separator 12, and a second electrode 13 stacked in sequence. The electrode assembly 10 can be a cylindrical electrode core formed by stacking the first electrode 11, the separator 12, and the second electrode 13 and then winding them around the center pin 60.

[0043] The separator 12 is placed between the first electrode 11 and the second electrode 13 and insulates them. For example, the separator 12 can include polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer structure of two or more layers thereof. The separator 12 can also include a hybrid multilayer structure, such as a polyethylene / polypropylene two-layer structure, a polyethylene / polypropylene / polyethylene three-layer structure, or a polypropylene / polyethylene / polypropylene three-layer structure.

[0044] The first electrode 11 and the second electrode 13 include coated regions 11a, 13a where active material layers are formed on both sides of a current collector formed of a thin metal plate, and uncoated regions 11b, 13b where no active material layer is formed and the current collector substrate is exposed. The uncoated regions 11b, 13b are located at opposite ends of the current collector, respectively. In some examples, the first electrode 11 can be a positive electrode and the second electrode 13 can be a negative electrode.

[0045] In the extreme core state, the first electrode current collector plate 11d is connected to the first uncoated area 11b of the electrode assembly 10, and the second electrode current collector plate 13d is connected to the second uncoated area 13b of the electrode assembly 10.

[0046] Although the second electrode current collector plate 13d is in contact with the housing 20, the first electrode current collector plate 11d is formed narrower than the second electrode current collector plate 13d, such that the first electrode current collector plate 11d is formed not to be in contact with the housing 20.

[0047] Refer to Figure 1 and Figure 2 , the uncoated area 11b of the first electrode 11 is bent toward the center pin 60 which is the center of the electrode assembly 10, and adjacent first uncoated areas 11b can be overlapped and stacked with each other for electrical connection.

[0048] The first uncoated area 11b can be electrically connected to the first electrode current collector plate 11d in an overlapped state.

[0049] The first uncoated area 11b includes one surface that is electrically connected by contacting the first electrode current collector plate 11d and another surface facing the end of the second electrode 13. This another surface is spaced apart from the end of the second electrode 13.

[0050] The first insulating layer 61 and the second insulating layer 62 with different lengths L1 and L2 are respectively formed on one surface and another surface of the first uncoated area 11b. The lengths L1 and L2 are respectively the lengths from the ends of the first insulating layer 61 and the second insulating layer 62 adjacent (e.g., meeting) to the first coated area 11a to the ends of the first insulating layer 61 and the second insulating layer 62 extending to the first uncoated area 11b exposed to the outside. The length L1 of the first insulating layer 61 can be shorter than the length L2 of the second insulating layer 62.

[0051] For example, the length L1 of the first insulating layer 61 can be about 2.5 mm to about 2.7 mm, and the length L2 of the second insulating layer 62 can be about 5.5 mm to about 5.9 mm.

[0052] The thicknesses of the first insulating layer 61 and the second insulating layer 62 can be less than 10 μm to facilitate laser grooving to form the electrode uncoated area (or electrode tab); however, the embodiments of the present disclosure are not limited thereto.

[0053] The first insulating layer 61 and the second insulating layer 62 can be thicker than the size of the burrs generated during the stamping step of the electrode uncoated area (or electrode tab) where the first electrode is formed (e.g., the combination of the first insulating layer 61 and the second insulating layer 62 can be thicker than this size), or thicker than the size of the burrs generated during the stamping between the electrode uncoated areas or the laser process for grooving. For example, if the size of the burrs is 15 μm, then each of the first insulating layer 61 and the second insulating layer 62 can be 20 μm or thicker.

[0054] The first uncoated area 11b includes a first area A extending from the first coated area 11a in a first direction (e.g., the longitudinal direction of the electrode assembly 10 / housing 20), and a second area B extending (e.g., bending) from the first area A (e.g., along a second direction intersecting the first direction) and overlapping with an adjacent first uncoated area 11b. For better understanding and ease of description, the first area A and the second area B can be divided by a dashed line S (as Figure 2 shown).

[0055] The first insulating layer 61 is formed in the first area A, and the second insulating layer 62 is formed from the first area A into the second area B. The end of the first insulating layer 61 is located on or below the dashed line S where the first uncoated area 11b bends. Due to the first insulating layer 61 and the second insulating layer 62 formed in the first area A, a short circuit with the second uncoated area 13b can be prevented.

[0056] To electrically connect the first uncoated area 11b to an adjacent first uncoated area 11b, the second insulating layer 62 is only formed in a part of the second area B, so as to form an exposed surface where the other part of the first uncoated area 11b is exposed. In other words, the second insulating layer 62 can be formed from the line S to the line S1 of an adjacent first uncoated area 11b.

[0057] The width W1 of the front exposed surface formed on one surface of the first uncoated area 11b can be greater than 4.25 mm, and the width W2 of the back exposed surface formed on the other surface of the first uncoated area can be greater than 1 mm.

[0058] In some examples, the first insulating layer 61 and the second insulating layer 62 can be formed of ceramics, NMP solvent is used as the solution, and the content of solid Al 2 O 3 can vary in the range of about 13% to about 30% according to the thickness of the first insulating layer 61 and the second insulating layer 62.

[0059] In Figure 2 it is shown that the second insulating layer 62 is formed to the line S1 of an adjacent first electrode 11, but it is not limited thereto, as Figure 3As shown, the end of the second insulating layer 62 may be positioned to extend beyond the line S1 of the adjacent first electrode 11.

[0060] Because the thickness of the first uncoated region 11b is thin and it is easily bendable, and the height of the second insulating layer 62 is low, the first uncoated region 11b can be easily bent along the end of the second insulating layer 62 and cover the end of the second insulating layer 62. Therefore, even if the second insulating layer 62 is located between the first uncoated region 11b and the adjacent first uncoated region 11b, it is possible to easily bring the first uncoated region 11b into contact with the adjacent first uncoated region 11b and electrically connect them.

[0061] The first coated region 11a includes a substrate 7 and an active material layer 8 formed on the substrate 7. The ends of the active material layer 8 adjacent to the first insulating layer 61 and the second insulating layer 62 are covered by the first insulating layer 61 and the second insulating layer 62.

[0062] The end of the active material layer 8 has an inclined surface inclined with respect to the substrate 7, and the first insulating layer 61 and the second insulating layer 62 may be formed on the inclined surface of the active material layer 8. By covering the inclined surface of the active material layer 8 with the insulating layers 61, 62, the thickness of the inclined surface can be compensated to reduce the thickness deviation at the center and the edge of the active material layer.

[0063] In some examples, the first insulating layer 61 and the second insulating layer 62 may overlap the active material layer 8 with a width W3 of 1 mm or less. If the overlapping width W3 of the insulating layer exceeds 1 mm, one end of the overlapping width W3 will pass through the inclined surface of the active material layer 8 and will be located on the portion of the active material layer 8 having a uniform thickness. As a result, a stepped or mountain-shaped protruding region due to the insulating layer locally appears, which may break the region where the adjacent electrode plates are stacked.

[0064] Referring to Figure 4 , when the first insulating layer 61 and the second insulating layer 62 are formed as in some embodiments, even when the active material layer 8 of the second electrode 13 expands and the second uncoated region 13b protrudes (e.g., bulges) during the charge and discharge cycle, the top of the second uncoated region 13b will contact the second insulating layer 62, so no short circuit will occur.

[0065] Referring again to Figure 1 , the lead tab 37 is electrically connected to the first electrode current collector plate 11d.

[0066] One end of the lead tab 37 may be connected to the first electrode current collector plate 11d by welding, and the other end may be electrically connected to the cover assembly 30. The lead tab 37 may be bent such that one surface faces the electrode assembly 10 to increase the contact area with the cover assembly 30.

[0067] An insulating plate 50 having an opening that exposes the center pin 60 is located above the first electrode current collector plate 11d.

[0068] The insulating plate 50 may be formed larger than the first electrode current collector plate 11d (for example, formed to have a diameter larger than the diameter of the first electrode current collector plate 11d), such that the insulating plate 50 can contact the inner surface of the housing 20. In this way, when the insulating plate 50 is formed larger than the first electrode current collector plate 11d, since the width of the insulating plate 50 protrudes beyond the first electrode current collector plate 11d (for example, protrudes outside the first electrode current collector plate 11d), a certain gap is formed between the first electrode current collector plate 11d and the housing 20. The gap between the first electrode current collector plate 11d and the housing 20 can prevent the phenomenon that the first electrode current collector plate 11d and the housing 20 come into contact with each other and short-circuit.

[0069] The lead tab 37 can be connected by contacting the first auxiliary plate 34 of the electrode assembly 10 to be described later through the opening 51 of the insulating plate 50.

[0070] Since the electrode assembly 10 is wound around the center pin 60, the center pin 60 can be located at the center of the electrode assembly 10 and is arranged parallel to the direction in which the electrode assembly 10 is inserted into the housing 20 (for example, the longitudinal direction of the electrode assembly 10 / housing 20).

[0071] When subjected to an overall compressive load or a local impact load acting from outside the rechargeable battery, the center pin 60 does not deform significantly (for example, to the lowest degree) or maintains a shape close to its shape before deformation.

[0072] The center pin 60 can be formed of a material having a certain rigidity (for example, a conductive metal) so as not to deform significantly (for example, to the lowest degree) when resisting external shocks. Thus, since the center pin 60 has conductivity, both ends of the center pin 60 are mounted to maintain an electrically insulated state on the first electrode current collector plate 11d and the second electrode current collector plate 13d.

[0073] That is, an insulating pad 52 is placed between the bottom of the center pin 60 and the corresponding second electrode current collector plate 13d. The top of the center pin 60 passes through a through hole formed in the center of the first electrode current collector plate 11d in an insulated state and is supported on the insulating plate 50. Here, the top of the center pin 60 can be spaced apart from the through hole of the first electrode current collector plate 11d, and an insulating member can be interposed therebetween. Therefore, the movement of the center pin 60 in the length direction of the center pin 60 is restricted, and the center pin 60 can maintain a stable state at the center of the electrode assembly 10.

[0074] The housing 20 has an opening on one side such that the electrode assembly 10 with electrolyte can be inserted, and the housing 20 can be formed to have a shape substantially the same as that of the electrode assembly 10 with the shape of the electrode core. For example, the housing 20 can be cylindrical.

[0075] The housing 20 can be connected to the second electrode current collector plate 13d of the electrode assembly and serve as the second electrode terminal of the rechargeable battery. In some examples, the housing 20 can be formed of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel.

[0076] The electrode assembly 10 can be inserted into the housing 20 together with the electrolyte solution and then sealed.

[0077] The electrolyte solution can be composed of organic solvents (such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC)) and lithium salts (such as LiPF 6 and LiBF 4 ). The electrolyte solution can be liquid, solid, or gel-like.

[0078] The cover assembly 30 is located in the opening of the housing 20 and is coupled to the housing 20 using a gasket 40 therebetween. The gasket 40 insulates the housing 20 and the cover assembly 30 and encloses and seals the interior of the housing 20 that houses the electrode assembly 10 and the electrolyte solution.

[0079] The cover assembly 30 includes a cover plate 31, a positive temperature coefficient element 35, an exhaust plate 32, an insulating member 33, a first auxiliary plate 34, and a second auxiliary plate 38.

[0080] The first auxiliary plate 34 can be electrically connected to the lead tab 37 of the electrode assembly and can be coupled to the lead tab 37 by welding.

[0081] The second auxiliary plate 38 can be stacked on the first auxiliary plate 34 and electrically connected to the first auxiliary plate 34, and can be connected to the first auxiliary plate 34 by welding. The second auxiliary plate 38 can be disposed at the center corresponding to the center pin 60 of the electrode assembly 10 to have a through hole that exposes the first auxiliary plate 34.

[0082] The exhaust plate 32 is disposed above the second auxiliary plate 38 and the insulating member 33 is between the exhaust plate 32 and the second auxiliary plate 38. The edge of the exhaust plate 32 can be inserted into the gasket 40 to be coupled to the housing 20.

[0083] The exhaust plate 32 includes an exhaust port 32a provided at a portion corresponding to the center pin 60. The exhaust port 32a protrudes from the exhaust plate 32 toward the electrode assembly 10 and is electrically connected to the first auxiliary plate 34 by contacting the first auxiliary plate 34 via a through hole. The exhaust plate 32 may have a notch 32b around the exhaust port 32a to guide the rupture of the exhaust port 32a.

[0084] The exhaust port 32a can cut off the electrical connection with the first auxiliary plate 34 by rupturing under set or predetermined pressure conditions to release the internal gas to the outside. That is, when the internal pressure of the housing 20 rises due to gas generation, the notch 32b can quickly rupture to allow the gas to be discharged to the outside through the discharge port 31d to be described later, thus preventing the rechargeable battery from exploding.

[0085] In addition, when the exhaust port 32a ruptures due to an abnormal reaction (e.g., an abnormal chemical reaction), the electrical connection between the exhaust plate 32 and the first auxiliary plate 34 ruptures. Therefore, the electrical connection between the cover plate 31 electrically connected to the exhaust plate 32 and the first auxiliary plate 34 is disconnected, and thus no current flows anymore.

[0086] The cover plate 31 includes a center plate 31a corresponding to the center pin 60 which is the center of the electrode assembly 10, a plurality of branch portions 31b extending from the center plate 31a toward the gasket 40, and a bonding plate 31c inserted and bonded into the gasket 40 to connect the ends of the branch portions 31b. The discharge port 31d is formed between adjacent branch portions 31b that open to the outside.

[0087] The branch portions 31b are connected to the center plate 31a in a bent state from the bonding plate 31c such that the center of the cover plate 31 can protrude to the outside of the housing 20. The cover plate 31 can be electrically connected to the first electrode current collector plate 11d through the exhaust plate 32, the second auxiliary plate 38, the first auxiliary plate 34, and the lead tab 37, thus serving as the first electrode terminal of the rechargeable battery. Therefore, by forming the center of the cover plate 31 to protrude to the outside of the housing 20, it is convenient to connect with the terminals of external devices.

[0088] The positive temperature coefficient element 35 can be formed along the second plate of the cover plate 31 and can be inserted and bonded into the gasket 40 while being stacked between the second plate of the cover plate and the edge of the exhaust plate.

[0089] The positive temperature coefficient element 35 can be installed between the cover plate 31 and the exhaust plate 32 to control the current between the cover plate 31 and the exhaust plate 32 according to the internal temperature of the rechargeable battery.

[0090] When the internal temperature is within a set or predetermined range, the positive temperature coefficient element 35 functions as a conductor to electrically connect the cover plate 31 and the exhaust plate 32. If the internal temperature exceeds the set or predetermined temperature, the resistance of the positive temperature coefficient element 35 increases sharply (e.g., increases to a very large value). Therefore, the positive temperature coefficient element 35 can block the flow of charging or discharging current between the cover plate 31 and the exhaust plate 32.

[0091] As the electrode assembly 10 is inserted into the housing 20, the cover assembly 30 is inserted into the gasket 40 in a form where the exhaust plate 32, the positive temperature coefficient element 35, and the cover plate 31 are stacked on the edge of the cover assembly 30, and then inserted into the opening of the housing 20.

[0092] Then, the cover assembly 30 is clamped to the opening of the housing 20 through a clamping process. A crimping portion 21 and a caulking portion 22 can be formed on a side adjacent to the opening of the housing 20. The crimping portion 21 can be formed through a crimping process. When the electrode assembly 10 is accommodated in the housing 20, the crimping portion 21 has a structure that is recessed from the upper side of the housing 20 toward the center in the diameter direction of the housing 20, and prevents the electrode assembly 10 from moving up and down or substantially reduces such movement.

[0093] The caulking portion 22 is connected to the crimping portion 21 in a structure that protrudes relatively more than the crimping portion 21 in the diameter direction, so as to hold the outer peripheral surface of the cover assembly 30 and the upper and lower surfaces of the cover assembly 30 connected to the outer peripheral surface by using the gasket 40 disposed between the upper and lower surfaces of the cover assembly 30.

[0094] It should be understood that the embodiments described herein should be considered in a descriptive sense and not for purposes of limitation. The description of features or aspects within each embodiment should generally be considered applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, those of ordinary skill in the art will understand that various changes in form and detail can be made therein without departing from the scope defined by the appended claims and their equivalents.

[0095] Explanation of reference numerals 10: Electrode assembly 11: First electrode 12: Separator 13: Second electrode 20: Housing 21: Crimping portion 22: Caulking portion 30: Cover assembly 31: Cover plate 31a: Center plate 31b: Branch portion 31c: Bonding plate 31d: Discharge port 32: Exhaust plate 32a: Exhaust port 32b: Notch 33: Insulating member 34: First auxiliary plate 35: Positive temperature coefficient element 37: Lead terminal 38: Second auxiliary plate 40: Washer 50: Insulating board 51: Opening 52: Insulating gasket 60: Central pin 61, 62: Insulating layer.

Claims

1. An electrode assembly, comprising: A first electrode including a first substrate and first active material layers formed on the front and back sides of the first substrate, respectively; A second electrode including a second substrate and second active material layers formed on the front and back surfaces of the second substrate, respectively; a separator between the first electrode and the second electrode; as well as A first insulating layer and a second insulating layer are formed on the front surface and the back surface of the first substrate, respectively, and cover the end of the first active material layer. The first insulating layer and the second insulating layer have different lengths.

2. The electrode assembly according to claim 1, wherein: One end of the first substrate, on which the first insulating layer and the second insulating layer are formed, is bent toward a center of the electrode assembly.

3. The electrode assembly according to claim 2, wherein: The length of the first insulating layer on the front surface of the first substrate is shorter than the length of the second insulating layer on the back surface of the first substrate and positioned closer to the center of the electrode assembly than the first insulating layer.

4. The electrode assembly according to claim 3, wherein: The length of the second insulating layer is 5.5 mm to 5.9 mm, and the length of the first insulating layer is 2.5 mm to 2.7 mm.

5. The electrode assembly according to claim 2, wherein: The first insulating layer and the second insulating layer are not formed on a portion of the first substrate, so that the first substrate further includes a front exposed portion and a back exposed portion exposing the first substrate, The width of the front exposed portion is greater than 4.25 mm, and Wherein, the width of the back exposed portion is greater than 1 mm.

6. The electrode assembly according to claim 5, wherein: The rear surface exposed portion is in direct contact with the front surface exposed portion of the next turn of the first substrate to be electrically connected with the front surface exposed portion of the next turn of the first substrate.

7. The electrode assembly according to claim 2, wherein: The second insulating layer faces an end portion of the second electrode and is spaced apart from the end portion of the second electrode.

8. The electrode assembly according to claim 1, wherein: The first insulating layer and the second insulating layer are formed of ceramic.

9. The electrode assembly according to claim 8, wherein: The ceramic includes Al2O3.

10. The electrode assembly according to claim 1, wherein: The thickness of the first insulating layer and the thickness of the second insulating layer are less than 10 μm.

11. The electrode assembly according to claim 1, wherein: The first electrode is a positive electrode, and Wherein, the second electrode is a negative electrode.

12. The electrode assembly according to claim 1, wherein: The thickness of the first insulating layer and the thickness of the second insulating layer are larger than a protruding size of a burr formed on a cut surface of the first electrode.

13. The electrode assembly according to claim 12, wherein: The thickness of the first insulating layer and the thickness of the second insulating layer are greater than 20 μm.

14. The electrode assembly according to claim 1, wherein: The first insulating layer and the second insulating layer overlap the end portion of the first active material layer with a width of 1 mm or less.

15. A rechargeable battery, comprising: The electrode assembly according to claim 1; a cylindrical housing configured to accommodate the electrode assembly; a center pin located at the center of the electrode assembly; a cover assembly, covering and sealing the cylindrical housing; as well as An electrolyte is housed in the cylindrical case together with the electrode assembly.

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