Cylindrical secondary battery

Abstract

A cylindrical secondary battery is provided. The cylindrical secondary battery includes an electrode assembly including a first electrode plate and a second electrode plate; a can having a bottom and a cylindrical side portion, accommodating the electrode assembly, and electrically connected to the first electrode plate; and a cap assembly. The cap assembly includes a cap plate bonded to one end of the side portion of the can and electrically connected to the second electrode plate; a gasket insulating the cap plate and the side portion from each other; and a sub plate covering at least a portion of the cap plate and at least a portion of a top of the side portion.

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2022-0007826, filed on January 19, 2022, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0002] An aspect of the embodiments of this disclosure relates to a cylindrical secondary battery. Background Technology

[0003] Typically, a cylindrical secondary battery includes a cylindrical electrode assembly, a cylindrical can containing the electrode assembly and electrolyte, and a cover assembly that is attached to a housing (e.g., the can) to seal the can and allow current generated (or stored) in the electrode assembly to flow to an external device.

[0004] Cylindrical secondary batteries can have a structure in which the casing (e.g., a can) serving as the negative electrode and the cover assembly serving as the positive electrode are insulated from each other by gaskets. In this configuration, the negative electrode is typically located at the bottom of the battery (or on the lower side or at the bottom end). However, in some cases, both the negative and positive electrodes should be located on one side of the battery. In such cases, the area for welding the negative terminal is narrow.

[0005] The information disclosed in this background section is intended to enhance the understanding of the background technology of this disclosure, and therefore may contain information that does not constitute prior art. Summary of the Invention

[0006] Embodiments of this disclosure provide a cylindrical secondary battery in which the negative and positive electrodes are arranged in one direction (e.g., at one end of the battery) and have an improved structure.

[0007] According to embodiments of this disclosure, a cylindrical secondary battery includes: an electrode assembly including a first electrode plate and a second electrode plate; a can having a bottom and cylindrical sides, housing the electrode assembly and electrically connected to the first electrode plate; and a cover assembly. The cover assembly includes: a cover plate coupled to one end of the side of the can and electrically connected to the second electrode plate; a gasket insulating the cover plate and the side from each other; and a sub-plate covering at least a portion of the cover plate and at least the top of the side.

[0008] The cover assembly may also include an insulating member comprising an insulating material and disposed between the sub-electrode and the cover electrode.

[0009] The can may have a rolled edge portion and a crimped portion, the rolled edge portion being adjacent to the open end of the side portion and curved inwardly, and the crimped portion being spaced apart from the rolled edge portion and being the curved end of the side portion. A sub-electrode plate may cover at least a portion of the crimped portion.

[0010] The cover plate may include a positive terminal protruding outward from the surface of the plate, and the sub-plate may include an annular substrate located between the outer edge of the positive terminal and the top of the washer.

[0011] The width or diameter of the substrate can be smaller than the distance between the outer edge of the positive terminal and the top of the washer.

[0012] The sub-electrode may also include multiple extensions and an arc-shaped curved portion, the multiple extensions extending outward from the outer edge of the substrate, and the curved portion extending from the end of each of the multiple extensions along the circumferential direction of the substrate.

[0013] At least a portion of the substrate, at least a portion of the extension, and the bent portion can be welded to the tank.

[0014] The cylindrical secondary battery may further include: a first electrode current collector electrically connected to a first electrode plate and electrically connected to the bottom; and a second electrode current collector electrically connected to a second electrode plate and electrically connected to a cover plate. The first electrode plate may be a negative electrode plate, and the second electrode plate may be a positive electrode plate. Attached Figure Description

[0015] Figure 1 This is a perspective view of a cylindrical secondary battery according to an embodiment of the present disclosure.

[0016] Figure 2 yes Figure 1 The image shows a cross-sectional view of a cylindrical secondary battery.

[0017] Figure 3 yes Figure 1 The diagram shows a plan view of the sub-electrode.

[0018] Figure 4 It is a combination of Figure 3 The diagram shows a plan view of a cylindrical secondary cell with a sub-electrode plate.

[0019] Figure 5 yes Figure 2 A magnified view of part A.

[0020] Figure 6 This is a plan view of the sub-electrode plate according to another embodiment of the present disclosure.

[0021] Figure 7 This is a perspective view schematically showing a sub-electrode plate according to another embodiment of the present disclosure. Detailed Implementation

[0022] Embodiments of this disclosure are provided to describe aspects and features of the disclosure more fully to those skilled in the art, and the following embodiments can be modified into various other forms. Therefore, this disclosure can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will convey aspects and features of the disclosure to those skilled in the art.

[0023] It will be understood that when an element or layer is referred to as being "on," "connected to," or "bonded to" another element or layer, the element or layer may be directly on, directly connected to, or directly bonded to the other element or layer, or one or more intermediary elements or intermediary layers may be present. When an element or layer is referred to as being "directly on," "directly connected to," or "directly bonded to" another element or layer, no intermediary element or intermediary layer is present. For example, when a first element is described as being "bonded" or "connected" to a second element, the first element may be directly bonded to or directly connected to the second element, or the first element may be indirectly bonded to or indirectly connected to the second element via one or more intermediary elements.

[0024] In the figures, the dimensions of various elements, layers, etc., may be exaggerated for clarity of illustration. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, when describing embodiments of this disclosure, the use of "may" refers to "one or more embodiments of this disclosure." Expressions such as "at least one of..." when preceding (or following) a list of elements modify the entire list of elements but not individual elements within that list. As used herein, the term "use" and its variations may be considered synonymous with the term "utilize" and its variations, respectively. As used herein, the terms "basically," "about," and similar terms are used as approximate terms rather than terms of degree and are intended to account for inherent variations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art.

[0025] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion.

[0026] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” and “above” are used herein to describe the relationship between one element or feature and another (other) element or feature shown in the figure. It will be understood that, in addition to the orientation depicted in the figure, the spatial relative terms are also intended to encompass different orientations of the device in use or operation. For example, if the device in the figure is flipped, an element described as “below” or “under” another element or feature will subsequently be oriented “above” or “above” said other element or feature. Thus, the term “below” can encompass both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein should be interpreted accordingly.

[0027] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to be limiting of this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a” and “an” are also intended to include the plural forms. It will also be understood that when the terms “comprising,” “including,” and / or variations thereof are used in this specification, they indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof.

[0028] In the following, a cylindrical secondary battery according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. Here, the upper part is defined as the reference. Figure 1 and Figure 2 The upper side or upper direction, the lower part is defined as the reference. Figure 1 and Figure 2 The lower side or the direction of the lower side.

[0029] Figure 1 This is a perspective view of a cylindrical secondary battery according to an embodiment of the present disclosure. Figure 2 yes Figure 1 The image shows a cross-sectional view of a cylindrical secondary battery. Figure 3 yes Figure 1 The diagram shows a plan view of the sub-electrode. Figure 4 It is a combination of Figure 3 The diagram shows a plan view of a cylindrical secondary cell with a sub-electrode plate. Figure 5 yes Figure 2 A magnified view of part A.

[0030] like Figure 1 and Figure 2As shown, the cylindrical secondary battery (or simply secondary battery) 10 may include a cylindrical can 110, an electrode assembly 130 inserted into (e.g., housed in) the can 110, a cap assembly 190 attached to one end of the can 110, and a first electrode current collector 150 and a second electrode current collector 170 electrically connecting the electrode assembly 130 to the can 110. The cap assembly 190 will be described in more detail later.

[0031] The can 110 has a circular bottom 112 and a side 114 extending upward from the bottom 112 to form a cylindrical shape in which the top of the side 114 is open (hereinafter referred to as an opening). During the manufacture of the secondary battery 10, the electrode assembly 130, together with the electrolyte, is inserted into the can 110 through the opening in the can 110. The electrode assembly 130 may be (e.g., respectively) electrically connected to the can 110 and the cover assembly 190 by (or through) a first electrode current collector 150 and a second electrode current collector 170. The can 110 may be made of steel, steel alloy, nickel-plated steel, nickel-plated steel alloy, aluminum, aluminum alloy, or equivalents thereof, but the material of the can 110 is not limited herein.

[0032] like Figure 1 and Figure 2 As shown, a through-hole for engaging (or providing) the vent 112a can be formed in the bottom 112 of the can 110, and the vent 112a can be engaged with the through-hole (e.g., inserted into the through-hole). The vent 112a can have a circular shape, an elliptical shape, etc., with a diameter (e.g., a predetermined diameter) on the circular bottom 112. In other embodiments, a notch (or groove) can be formed in the inner surface (e.g., the surface facing the electrode assembly 130) and / or the outer surface (e.g., the surface facing the outside of the can 110) of the bottom 112 by forging (or machining). If the pressure inside the can 110 increases due to an increase in the internal pressure of the battery or an increase in gas production caused by internal or external factors, the vent 112a or the notch can rupture (e.g., break), and the gas can be released. Therefore, a vent may not be provided in the cover assembly 190, which will be described later.

[0033] like Figure 1 and Figure 2As shown, a rolled edge portion (e.g., rolled edge) 114a, machined (or pressed) inwardly recessed along the outer circumferential surface of the can 110, may be formed adjacent to an opening in the side portion 114. When the cap assembly 190 is placed on the rolled edge portion 114a, the top end of the can 110 is bent inward (e.g., crimped) to secure the cap assembly 190. The bent end is referred to as a crimped portion (e.g., crimp end) 114b, which may be electrically connected to the cap assembly 190, as will be described later. When the electrolyte and electrode assembly 130 is housed in the can 110, the cap assembly 190 may be engaged with the can 110 at an opening in the can 110 to close the opening.

[0034] Electrode assembly 130 includes a first electrode plate, a second electrode plate, and a separator. The first electrode plate may be a negative electrode plate having a negative electrode active material layer (e.g., graphite, carbon, etc.) formed on both surfaces. Uncoated portions of the first electrode where no negative electrode active material layer is applied may be formed at a portion of the first electrode plate (e.g., at the end of the first electrode plate). The second electrode plate may be a positive electrode plate having a positive electrode active material layer (e.g., transition metal oxide (LiCoO2, LiNiO2, LiMn2O4, etc.)) formed on both surfaces. Uncoated portions of the second electrode where no positive electrode active material layer is applied may be formed at a portion of the second electrode plate (e.g., at the end of the second electrode plate). The separator may be disposed between the first and second electrode plates to prevent short circuits between the first and second electrode plates while allowing lithium ions to move. The first electrode plate may be made of copper (Cu) foil or nickel (Ni) foil, the second electrode plate may be made of aluminum (Al) foil, and the separator may be made of polyethylene (PE) or polypropylene (PP), but this disclosure is not limited to the materials listed herein.

[0035] The first electrode plate, the second electrode plate, and the partition can be wound into a generally cylindrical shape and housed in the can 110. The first electrode plate and the second electrode plate can be arranged such that, when wound, the uncoated portions of the first electrode and the second electrode, to which no corresponding active material (or active material layer) is applied, are positioned in opposite directions (e.g., at opposite ends of the electrode assembly 130).

[0036] For example, refer to Figure 2 The first electrode plate, serving as the negative electrode plate, can be configured such that the uncoated portion of the first electrode faces downwards (e.g., towards the bottom 112 of the can 110). See reference... Figure 2The second electrode plate, serving as the positive electrode plate, can be configured such that the uncoated portion of the second electrode faces upward (e.g., toward the cap assembly 190). A separator can be disposed between the first and second electrode plates, and the electrode assembly 130 can be wound up when the first and second electrode plates are insulated from each other by the separator. Subsequently, the first electrode current collector 150 can be electrically connected to the uncoated portion of the first electrode, and the second electrode current collector 170 can be electrically connected to the uncoated portion of the second electrode. Thus, as described later, the can 110 and the cap assembly 190 can subsequently be electrically connected to the electrode assembly 130.

[0037] The first electrode current collector 150 can be electrically connected to the bottom 112 of the can 110 by welding. Because the first electrode current collector 150 is electrically connected to the uncoated portion of the first electrode, it can be used as a negative current collector. The second electrode current collector 170 can be electrically connected to the cover assembly 190 via current collector leads 172. Because the second electrode current collector 170 is electrically connected to the uncoated portion of the second electrode, it can be used as a positive current collector.

[0038] like Figure 1 and Figure 2 As shown, the cover assembly 190 may include a cover plate 191, a positive terminal 192 disposed at the center of the cover plate 191, a sub-plate 194 attached to the outside of the cover plate 191, an insulating member 195 for insulating the sub-plate 194 and the cover plate 191 from each other, and a gasket 196 for insulating the cover plate 191 and the can 110 from each other.

[0039] The cover plate 191 has a generally circular shape, and the positive terminal 192 can be disposed at the center of the cover plate 191. For example, the positive terminal 192 can protrude beyond the cover plate 191. (Refer to...) Figure 2 The positive terminal 192 may have a cylindrical shape that projects upward from the center of the upper surface (e.g., the electrode surface) of the cap electrode 191. The positive terminal 192 may be integrally formed with the cap electrode 191, or it may be formed separately and subsequently bonded to the cap electrode 191 by welding or the like. In the illustrated embodiment, as an example, the positive terminal 192 is integrally formed with the cap electrode 191.

[0040] Because the cover plate 191 is electrically connected to the positive electrode plate of the electrode assembly 130 by (or through) a second electrode current collector 170 serving as the positive current collector and a current collector lead 172 connected thereto, the cover plate 191 can be used as the positive electrode. In some embodiments, the positive terminal 192 may not be provided (e.g., it may not be provided protrudingly or configured to protrude above the cover plate 191), and only the cover plate 191 can be used as the positive terminal. The cover plate 191 may be made of the same or similar material as the can 110. The cover plate 191 may be disposed on the crimped portion 114a. The outer edge of the cover plate 191 may be insulated from the side 114 of the can 110 by a gasket 196.

[0041] Reference Figures 3 to 5 After securing the cap assembly 190 to the can 110, the sub-electrode 194 is positioned at the top of the side 114. The sub-electrode 194 may be made of the same or similar material as the can 110. The sub-electrode 194 includes an annular base 194a having a diameter or width (e.g., a predetermined diameter or width), a plurality of extensions 194b extending outward from the outer edge of the base 194a, and an arc-shaped curved portion 194c extending a certain length (e.g., a predetermined length) along the circumferential direction of the base 194a from the end of the extensions 194b. The base 194a may have a certain diameter to form (e.g., at its center) a hollow portion (e.g., an opening) such that the sub-electrode 194 does not contact the positive terminal 192. For example, in an embodiment, the width or diameter of the base 194a may be smaller than the distance between the outer edge of the positive terminal 192 and the top of the gasket 196. The extension 194b can be positioned to substantially cover the end of the washer 196 and the crimping portion 114b. The bent portion 194c can be bent along the curved surface of the crimping portion 114b to cover a portion of the top of the side portion 114. Therefore, as... Figure 4 As shown, the curved portion 194c is not visible when viewed from above the secondary battery 10.

[0042] although Figure 3The embodiment shown includes a plurality of curved portions 194c spaced apart from each other at regular intervals (or “spacing”), but in other embodiments, the curved portions 194c may be joined to form a single loop shape. After the cap electrode 191 is placed on the crimped portion 114a together with the gasket 196, a crimped portion 114b may be formed on (or above) the gasket 196 to secure the cap electrode 191. Then, the sub-electrode 194 may be placed to position the curved portions 194c. At least a portion of the base 194a (e.g., the outer edge), the extension portion 194b (e.g., at least a portion thereof), and the curved portions 194c may then be welded to and secured to the can 110. Welding methods may include ultrasonic welding, laser welding, resistance welding, etc. In this way, the sub-electrode 194 may be welded to the can 110 for electrical connection to the can 110, and the first electrode current collector 150, which is electrically connected to the negative electrode plate, may be connected to the can 110. Therefore, the sub-electrode 194 has the same polarity as the can 110 and can thus be used as the negative electrode. Furthermore, because the base 194a of the sub-electrode 194 is configured to connect to the crimped portion 114a, the area of ​​the crimped portion 114a can also be used as the negative electrode. This increases the area available for welding the negative electrode to the outside (e.g., to an external device or component), thereby improving welding convenience. A ring-shaped insulating member 195 for insulation can be inserted between the base 194a and the cover electrode 191.

[0043] like Figure 2 , Figure 4 and Figure 5 As shown, the insulating member 195 may be made of an insulating material and has a generally annular shape. The insulating member 195 may have a width such that the end of the washer 196 does not contact the outer edge of the positive terminal 192. However, the insulating member 195 is made of the same insulating material as the insulating material of the washer 196, and therefore can contact the end of the washer 196.

[0044] The gasket 196 is made of an insulating material and is shaped to surround the outer edge of the cover plate 191 (e.g., extend around the outer edge of the cover plate 191). One end (e.g., the distal end) of the gasket 196 extends beyond the end of the crimped portion 114a to insulate the side 114 of the can 110 from the cover plate 191.

[0045] With the cover assembly constructed as described above, both the positive and negative terminals can be positioned on the upper part of the secondary battery, and the welding area of ​​the negative terminal is increased to include the rolled edge area, thereby improving welding convenience.

[0046] However, the aforementioned sub-electrode plates can be modified in various forms.

[0047] Figure 6This is a plan view showing a sub-electrode plate according to another embodiment of the present disclosure. Figure 7 This is a perspective view schematically showing a sub-electrode plate according to another embodiment of the present disclosure.

[0048] like Figure 6 As shown, the sub-electrode 194' may have a ring shape in which the extended portions and / or bent portions of the above embodiments are omitted. In another embodiment, as... Figure 7 As shown, the sub-plate 194” can have a cylindrical shape with an open bottom, similar to an inverted cup. Even in Figure 6 and Figure 7 In the embodiment shown, the sub-electrode plates 194' and 194" may also have hollow portions (e.g., openings) formed in their top surfaces to prevent the sub-electrode plates 194' and 194" from contacting the positive terminal 192. According to... Figure 6 and Figure 7 The sub-electrodes 194' and 194" of the embodiment shown can be attached to according to Figures 1 to 5 The embodiment shown has a cover assembly 190, with an insulating member 195 disposed between the sub-electrode plates 194' and 194" and the cover plate 191.

[0049] As described above, according to embodiments of this disclosure, since both the positive and negative electrodes are positioned in one direction of the secondary battery (e.g., at one end of the secondary battery), the connection structure with external terminals (or external devices) can be simplified. Furthermore, because an additional area for soldering the negative terminal is provided, the flatness of the area for soldering the negative terminal can be improved, thus facilitating the soldering of the negative terminal.

[0050] Although the foregoing embodiments are merely some embodiments for implementing this disclosure (this disclosure is not limited to these embodiments), those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents.

Claims

1. A cylindrical secondary battery, the cylindrical secondary battery comprising: The electrode assembly includes a first electrode plate and a second electrode plate; A can, having a bottom and cylindrical sides, accommodates the electrode assembly and is electrically connected to the first electrode plate; as well as A cover assembly includes: a cover electrode plate, coupled to one end of the side portion of the can and electrically connected to a second electrode plate; a gasket, insulating the cover electrode plate and the side portion from each other; and a sub-electrode plate, covering at least a portion of the cover electrode plate and at least the top of the side portion. The can has a rolled edge portion and a crimped portion. The rolled edge portion is adjacent to the open end of the side portion and is curved inwardly. The crimped portion is spaced apart from the rolled edge portion and is the curved end of the side portion. The sub-electrode plate includes a ring-shaped substrate with a certain width or diameter, and The sub-electrode plate further includes multiple extension portions and an arc-shaped curved portion. The multiple extension portions extend outward from the outer edge of the substrate and are disposed at the end covering the gasket and the position of the crimping portion. The curved portion extends from the end of each of the multiple extension portions along the circumferential direction of the substrate and bends along the curved surface of the crimping portion.

2. The cylindrical secondary battery according to claim 1, wherein, The cover assembly further includes an insulating member comprising an insulating material and disposed between the sub-electrode plate and the cover electrode plate.

3. The cylindrical secondary battery according to claim 2, wherein, The sub-electrode plate covers at least a portion of the crimped portion.

4. The cylindrical secondary battery according to claim 3, wherein, The cover plate includes a positive terminal protruding outward from the surface of the plate, and The substrate is located between the outer edge of the positive terminal and the top of the washer.

5. The cylindrical secondary battery according to claim 4, wherein, The width or diameter of the substrate is less than the distance between the outer edge of the positive terminal and the top of the washer.

6. The cylindrical secondary battery according to claim 5, wherein, At least a portion of the substrate, at least a portion of the extension, and the bent portion are welded to the tank.

7. The cylindrical secondary battery according to claim 1, further comprising: The first electrode current collector is electrically connected to the first electrode plate and electrically connected to the bottom. as well as The second electrode current collector is electrically connected to the second electrode plate and also electrically connected to the cover electrode plate. The first electrode plate is the negative electrode plate, and the second electrode plate is the positive electrode plate.

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