Secondary battery

Abstract

A secondary battery includes a case having an internal space, an electrode assembly received in the internal space of the case, a current collector electrically connected to the electrode assembly, and a cover assembly. The cover assembly includes a cover plate sealing the case, an electrode terminal coupled to the current collector through the cover plate, and a gasket between the electrode terminal and the cover plate. The gasket has a flange portion, and the flange portion of the gasket is between an upper surface of the cover plate and the electrode terminal.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2021-0171828, filed on December 3, 2021, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Various aspects of the embodiments of this disclosure relate to secondary batteries. Background Technology

[0004] Unlike primary batteries, which are designed to be non-rechargeable, secondary batteries are designed to be both rechargeable and dischargeable. Low-capacity secondary batteries, consisting of a single cell packaged in a pack, are used in a variety of portable small electronic devices, such as mobile phones or portable cameras. High-capacity secondary batteries, with dozens of cells connected in a battery pack, are widely used as power sources for motor drives, such as those in hybrid or electric vehicles.

[0005] When such secondary batteries are installed in electronic devices or vehicles, they are exposed to vibrations or shocks caused by the external environment. Furthermore, repeated vibrations or shocks can affect the internal structure of the secondary battery, potentially causing malfunctions. Accordingly, it is desirable to provide a structure for mitigating vibrations or shocks applied to the secondary battery. Summary of the Invention

[0006] According to embodiments of this disclosure, a secondary battery is provided that has increased electrode terminal connection strength and increased internal space efficiency.

[0007] According to one embodiment of this disclosure, a secondary battery includes: a housing having an internal space; an electrode assembly housed within the internal space of the housing; a current collector electrically connected to the electrode assembly; and a cover assembly. The cover assembly includes: a cover plate sealing the housing; electrode terminals coupled to the current collector and extending through the cover plate; and a gasket between the electrode terminals and the cover plate. The gasket has a flange portion between the upper surface of the cover plate and the electrode terminals.

[0008] The electrode terminal may include a flange portion extending in a direction parallel to the upper surface of the cover plate, and a gasket may extend from the upper surface of the cover plate along the flange portion of the electrode terminal.

[0009] The electrode terminal may include a flange portion extending in a direction parallel to the upper surface of the cover plate, and the flange portion of the electrode terminal may be coupled to the upper surface of the liner.

[0010] The flange portion may extend along the outer periphery of the body portion of the electrode terminal, and the electrode terminal may be connected to the cover plate via the flange portion of the electrode assembly and a gasket extending around the lower part of the body portion.

[0011] The secondary battery may further include a fastening plate attached to the upper surface of the cover.

[0012] The fastening plate may have terminal holes through which the power supply terminals pass and protrusions protruding from the inside of the terminal holes, and the protrusions of the fastening plate may be connected to the end of the pad.

[0013] The electrode terminal may include a flange portion extending in a direction parallel to the upper surface of the cover plate, and the protrusion of the fastening plate may be outside the flange portion of the electrode terminal.

[0014] The secondary battery may further include a retainer. The current collector may include a first region coupled to the electrode assembly and a second region extending from the first region and coupled to the electrode terminals, and the retainer may be coupled to the lower portion of the second region of the current collector.

[0015] The retainer can extend along the second zone in a direction parallel to the upper surface of the cover plate.

[0016] The secondary battery may include an insulating plate between the electrode assembly and the cover plate, and a retainer may be attached to the insulating plate. Attached Figure Description

[0017] Figure 1 This is a perspective view of a secondary battery according to an embodiment of the present disclosure.

[0018] Figure 2 for Figure 1 An exploded perspective view of the secondary battery shown in the image.

[0019] Figure 3 For along Figure 1 The cross-sectional view taken by line A-A' in the diagram.

[0020] Figure 4 To show Figure 3 A magnified view of part B in the image. Detailed Implementation

[0021] The embodiments of this disclosure will now be described in detail to enable those skilled in the art to readily implement the embodiments with reference to the accompanying drawings.

[0022] It will be understood that when an element or layer is referred to as being "on" another element or layer, "connected to," or "linked to" another element or layer, it may be directly on, directly connected to, or linked to the other element or layer, or one or more intermediary elements or layers may be present. When an element or layer is referred to as being "directly on" another element or layer, "directly connected to," or "directly linked to" another element or layer, no intermediary element or layer is present. For example, when a first element is described as being "linked" or "connected" to a second element, the first element may be directly linked to or connected to the second element, or the first element may be indirectly linked to or connected to the second element via one or more intermediary elements.

[0023] In the accompanying drawings, the dimensions of various elements, layers, etc., may be enlarged for clarity. 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 related 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" placed before the list of elements modify the entire list of elements, not individual elements in the list. As used herein, the terms "use" and "be used" may be considered synonymous with the terms "utilize" and "be exploited," respectively. As used herein, the terms "substantially," "about," and similar terms are used as approximate terms rather than terms of degree and are intended to describe inherent biases in measured or calculated values ​​that would be recognized by one of ordinary skill in the art.

[0024] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, areas, layers, and / or segments, these elements, components, areas, layers, and / or segments should not be limited by these terms. These terms are used to distinguish one element, component, area, layer, or segment from another element, component, area, layer, or segment. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, area, layer, or segment discussed below may be referred to as the second element, component, area, layer, or segment.

[0025] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “up,” etc., may be used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. It will be understood that, in addition to the orientations depicted in the figures, spatial relative terms are intended to include different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features would be oriented as “above” or “upon” other elements or features. Therefore, the term “below” can include both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein should be interpreted accordingly.

[0026] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to limit this disclosure. As used herein, the singular forms “a” and “an” are also intended to include the plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprising” and / or “including” as used in this specification specify the presence of the described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0027] Figure 1 This is a perspective view of a secondary battery according to an embodiment of the present disclosure. Figure 2 for Figure 1 An exploded perspective view of the secondary battery shown in the image. Figure 3 For along Figure 1 The cross-sectional view taken by line A-A' in the diagram. Figure 4 To show Figure 3 A magnified view of part B in the image.

[0028] Reference Figures 1 to 4 According to an embodiment of the present disclosure, a secondary battery 100 includes an electrode assembly 110, a current collector 120, a retainer 130, an insulating plate 140, a cover assembly 150, and a housing 160.

[0029] The electrode assembly 110 is formed by stacking or winding a laminate of a first electrode plate, a diaphragm, and a second electrode plate in the shape of a sheet or a film. The first electrode plate may serve as a negative electrode, and the second electrode plate may serve as a positive electrode. Of course, in other embodiments, the first and second electrode plates may have any polarity, as long as they have different polarities from each other.

[0030] The first electrode plate is formed by coating a first electrode current collector, made of a metal foil such as copper or nickel, with a first electrode active material such as graphite or carbon, and includes an uncoated portion of the first electrode, which is the area where the first electrode active material is not applied. The uncoated portion of the first electrode provides a channel for current flow between the first electrode plate and the outside. The material of the first electrode plate is not limited to the examples above.

[0031] Additionally, the uncoated portion of the first electrode of the first electrode plate can form a first current collector tab 111. Multiple first current collector tabs 111 can be formed to protrude from the first electrode plate. In embodiments with a stacked structure, the first current collector tabs 111 can be formed to protrude from the first electrode plate in one direction (e.g., a predetermined direction) to overlap on one side. Alternatively, in embodiments with a winding (or coiling) structure, the first current collector tabs 111 can be formed by arranging the uncoated portion at a distance (e.g., a pre-calculated distance) from the first electrode plate, such that after winding, the first current collector tabs 111 protrude from the same area to overlap. Because the first current collector tabs 111 are integrally formed with the first electrode plate and are led out from (e.g., extended from) each of the first electrode plates, the current collection efficiency from the electrode assembly 110 can be increased. However, in other embodiments, the first current collector tabs 111 can be formed using separate components different from the first electrode plate.

[0032] The second electrode plate is formed by coating a second electrode current collector, such as a transition metal oxide, onto a second electrode current collector made of a metal foil such as aluminum, and may include uncoated portions of the second electrode, which are areas where the second electrode active material is not applied. Additionally, a second current collector tab 112 may be formed from the uncoated portions of the second electrode plate, corresponding to the first current collector tab 111. Accordingly, similar to the first current collector tab 111, the second current collector tab 112 may also have a multi-tab structure. Furthermore, the material of the second electrode plate is not limited to the examples described above.

[0033] A separator is located between the first and second electrode plates to prevent short circuits between them and to allow lithium ions to move. The separator can be made of polyethylene, polypropylene, or a composite membrane of polyethylene and polypropylene. The material of the separator is not limited to the examples above.

[0034] Electrode assembly 110 may be substantially housed within housing 160 along with the electrolyte. The electrolyte may include lithium salts such as LiPF6 or LiBF4 in an organic solvent such as ethylene glycol carbonate (EC), propylene glycol carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC). The electrolyte may be in liquid, solid, or gel form.

[0035] The first current collector 111 and the second current collector 112 are electrically connected to the current collector 120. A pair of current collectors 120 may be provided and may be electrically connected to the first current collector 111 and the second current collector 112 of the electrode assembly 110, respectively. The current collectors 120 are respectively connected to the first current collector 111 and the second current collector 112 of the electrode assembly 110. For example, the current collectors 120 are in contact with the first current collector 111 and the second current collector 112 protruding from the side of the electrode assembly 110, and in this state, they can be joined together by a process such as welding. Accordingly, the current collectors 120 may be electrically connected to each of the first current collector 111 and the second current collector 112. For example, the current collector 120 electrically connected to the first current collector 111 may have a negative polarity, and the current collector 120 electrically connected to the second current collector 112 may have a positive polarity.

[0036] Each of the current collectors 120 may include a first region (e.g., a first portion) 121 and a second region (e.g., a second portion) 122. In some embodiments, the first region 121 may be arranged in a direction parallel to the first current collector tab 111 or the second current collector tab 112 of the electrode assembly 110, and in this configuration, the first current collector tab 111 and the second current collector tab 112 may be soldered to the first region 121. Additionally, the second region 122 may be coupled to the first region 121 at its upper portion 121b (e.g., the upper end or upper region) via a process such as soldering. However, in some embodiments, the first region 121 and the second region 122 may be provided integrally.

[0037] Accordingly, the current collector 120 having a first zone 121 and a second zone 122 connected thereto can have the same polarity as the first current collector terminal 111 and the second current collector terminal 112.

[0038] The retainer 130 can be coupled to the lower portion of the second region 122 of the current collector 120. The retainer 130 is made of an electrical insulator and can connect the current collector 120 to an insulating plate 140 located on the current collector 120. For this purpose, the retainer 130 may have upwardly projecting hooks 131 in at least two regions, and can be fastened to the insulating plate 140 by means of the hooks 131. Accordingly, the second region 122 of the current collector 120 is fixed to the insulating plate 140, and the electrode assembly 110 coupled to the first region 121 of the current collector 120 can be held coupled to the insulating plate 140. In one embodiment, the retainer 130 may extend along the second region 122 in a direction parallel to the upper surface of the cover plate 151.

[0039] The insulating plate 140 may extend horizontally parallel above the electrode assembly 110. The insulating plate 140 may be made of an insulating polymer such as polypropylene (PP), polyethylene (PE), or polystyrene (PS). The insulating plate 140 may have a vent (e.g., vent port) 141 located substantially at the center of the electrode assembly 110 in the horizontal direction, an injection port (e.g., injection port) 142 formed to be spaced apart from one side of the vent 141, and terminal holes (e.g., terminal openings) 143 located at both ends of the insulating plate 140 in the horizontal direction.

[0040] Additionally, the insulating plate 140 may have a hook fastening groove 145 formed in a portion of the side surface 144 to fasten to the hook 131 of the retainer 130 described above. For example, the hook 131 of the retainer 130 protrudes upward through the hook fastening groove 145 in the insulating plate 140, and the lower end of the hook 131 can be engaged on the upper surface of the insulating plate 140, thereby maintaining a fastened state.

[0041] The cover assembly 150 is formed on the insulating plate 140 and coupled to the housing 160 to seal the housing 160. For example, the cover assembly 150 may include a cover plate 151, a fastening plate 152, a gasket 153, an electrode terminal 154, and a terminal plate 155.

[0042] Cover plate 151 is formed in a plate shape, attaches to an opening in housing 160, and may be made of the same material as housing 160. Cover plate 151 may be attached to housing 160, for example, by laser welding. In various embodiments, cover plate 151 may be electrically independent (e.g., electrically neutral) or electrically connected to a first current collector 111 or a second current collector 112. For example, cover plate 151 may be electrically connected to the second current collector 112, and in such embodiments, cover plate 151 and housing 160 have the same polarity (e.g., positive). In other embodiments, cover plate 151 may be electrically connected to the first current collector 111.

[0043] A vent (e.g., a vent opening) 151a may be formed at approximately the center of the cover plate 151, and a safety vent 151b, which is formed to have a relatively small thickness compared to other areas, may be formed within the vent 151a. If the internal pressure of the housing 160 becomes higher than the rupture pressure, the safety vent 151b ruptures (e.g., bursts) to prevent the secondary battery 100 from exploding.

[0044] Additionally, an electrolyte injection port (e.g., electrolyte inlet) 151c for injecting electrolyte may be formed on one side of the cover plate 151. Electrolyte is injected into the housing 160 through the electrolyte injection port 151c, which is then sealed by a plug.

[0045] Additionally, terminal holes (e.g., terminal openings) 151d through which electrode terminals 154 pass are formed on both sides of cover plate 151, and gasket 153 and electrode terminals 154 are respectively connected to terminal holes 151d.

[0046] Additionally, the fastening protrusion 151e formed around the terminal hole 151d may be further formed on both sides of the cover plate 151, and the area where the terminal hole 151d and the fastening protrusion 151e are located may be lower than the cover plate 151 by means of a fully engraved area (e.g., by means of a recessed area located in the cover plate 151). Accordingly, the position of the fastening plate 152 may be fixed by means of the engraved area (or within the engraved area) and the fastening protrusion 151e in the engraved area.

[0047] A pair of fastening plates 152 may be provided and may be respectively attached to both sides of the upper surface of the cover plate 151. The fastening plates 152 are located in an engraved area formed in the upper surface of the cover plate 151 and may be attached to the fastening protrusion 151e of the cover plate 151 via a fastening protrusion 152a. In addition, each of the fastening plates 152 may receive a pad 153 and an electrode terminal 154 through a terminal hole formed therein. In addition, the fastening plate 152 further includes a protrusion 152b protruding from the inside of the terminal hole for a certain length (e.g., a predetermined length), the protrusion 152b pressing the pad 153 (described later) from above to fix the position of the pad 153.

[0048] The gasket 153 is made of insulating material and is connected to the terminal hole of the fastening plate 152 to seal the area between the electrode terminal 154 and the fastening plate 152. The gasket 153 prevents external moisture from penetrating into the secondary battery 100 and prevents the electrolyte contained in the secondary battery 100 from leaking to the outside.

[0049] The gasket 153 has a flange portion 153a at its upper end, the flange portion 153a extending horizontally from the upper surface of the cover plate 151. (Refer to...) Figure 4 The flange portion 153a of the gasket 153 is located between the upper surface of the cover plate 151 and the electrode terminal 154. Accordingly, the electrolyte will not leak between the electrode terminal 154 and the cover plate 151.

[0050] Additionally, the flange portion 153a can be secured by pressing the upper surface of the edge against a protrusion 152b formed in the terminal hole of the fastening plate 152. Alternatively, the flange portion 153a can be secured by pressing the upper surface of the flange portion 153a against the inner side of the edge against an electrode terminal 154. Accordingly, the flange portion 153a and the gasket 153 having the flange portion 153a can be secured between the electrode terminal 154 and the cover plate 151.

[0051] When viewed relative to cover 151, the gasket 153 is located outside cover 151. Accordingly, the battery capacity can be increased because the internal space of the secondary battery separated by cover 151 and housing 160 is increased.

[0052] Electrode terminals 154 are connected through holes (e.g., openings) formed in the gasket 153, and correspondingly, electrode terminals 154 can be sequentially connected to a fastening plate 152, a cover plate 151, an insulating plate 140, and a second region 122 of a current collector 120 located below electrode terminals 154. Electrode terminals 154 may include: a first riveting portion 154a provided at the lower end of the body portion surrounding the electrode terminal 154 and connected to the second region 122 of the current collector 120; a flange portion 154b located at approximately the center height of the body portion for connection to the upper surface of the gasket 153; and a second riveting portion 154c provided at the upper end of the body portion for connection to a terminal plate 155.

[0053] The first riveting portion 154a may be formed to protrude along the lower end of the main body portion. The first riveting portion 154a may contact the second region 122 of the current collector 120 and may be fastened to the second region 122 by riveting deformation. Accordingly, through the first riveting portion 154a, the electrode terminal 154 has the same polarity as the current collector 120.

[0054] A flange portion 154b extends horizontally from approximately the center of the electrode terminal 154. The flange portion 154b may extend along the outer periphery of the body portion of the electrode terminal 154. When the first riveting portion 154a, together with the gasket 153, passes through and engages with the terminal hole 151d in the cover plate 151, the flange portion 154b presses against the upper surface of the flange portion 153a of the gasket 153. The electrode terminal 154 can be engaged to the cover plate 151 via the flange portion 154b and the gasket 153 extending around the lower portion of the body portion. Accordingly, the flange portion 154b can secure the gasket 153 and increase the sealing force. Furthermore, the engagement area between the flange portion 154b and the gasket 153 is located outside the cover plate 151. Consequently, the internal space in the housing 160 can be increased, thereby increasing battery capacity and efficiency.

[0055] The second riveted portion 154c can protrude upward from the main body and can be riveted to the terminal plate 155 located at the uppermost part. In addition, a separate welding process can be performed along the edge of the riveted second riveted portion 154c.

[0056] Terminal plate 155 is connected to electrode terminal 154 which protrudes from the cover plate 151 through terminal hole 151d in cover plate 151. After terminal plate 155 is connected to electrode terminal 154, second riveting portion 154c of electrode terminal 154 is riveted or welded together to terminal plate 155, thereby fixing electrode terminal 154 to terminal plate 155.

[0057] The housing 160 may be made of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel, and has a substantially hexahedral shape. The housing 160 has an opening through which the electrode assembly 110 can be inserted and positioned. A cover plate 151 is coupled to the housing 160 at this opening to seal the housing 160. The inner surface of the housing 160 is insulated to prevent short circuits. Additionally, in some embodiments, one electrode of the electrode assembly 110 may be electrically connected to the housing 160 via the cover plate 151. In such embodiments, internal insulation prevents electrical short circuits within the housing 160. In such embodiments, the housing 160 may function as a positive electrode.

[0058] As described above, the secondary battery according to an embodiment of the present disclosure includes a pad connected to the electrode terminals. Because the fastening portion between the electrode terminals and the pad is located outside the cover, the internal space in the housing is increased, thereby increasing the battery capacity.

[0059] The foregoing embodiments are merely some examples of implementing a secondary battery according to this disclosure, and this disclosure is not limited to the above 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 secondary battery comprising: a case having an internal space; an electrode assembly accommodated in the internal space of the case; a current collector electrically connected to the electrode assembly; and a cover assembly including: a cover plate sealing the case; an electrode terminal coupled to the current collector and extending through the cover plate; a gasket between the electrode terminal and the cover plate and having a flange portion, the flange portion of the gasket being between an upper surface of the cover plate and the electrode terminal; and a fastening plate having a terminal hole through which the electrode terminal passes and a protrusion protruding from an inner side of the terminal hole, wherein the protrusion of the fastening plate contacts an upper surface of the flange portion of the gasket. 2.The secondary battery of claim 1, wherein the electrode terminal includes a flange portion extending in a direction parallel to the upper surface of the cover plate, and wherein the flange portion of the gasket extends from the upper surface of the cover plate along the flange portion of the electrode terminal. 3.The secondary battery of claim 1, wherein the electrode terminal includes a flange portion extending in a direction parallel to the upper surface of the cover plate, and wherein the flange portion of the electrode terminal is coupled to an upper surface of the gasket. 4.The secondary battery of claim 3, wherein the flange portion of the electrode terminal extends along an outer periphery of a body portion of the electrode terminal, and wherein the electrode terminal is coupled to the cover plate by the flange portion of the electrode terminal and the gasket extending around a lower portion of the body portion. 5.The secondary battery of claim 1, wherein the fastening plate is coupled to the upper surface of the cover plate. 6.The secondary battery of claim 5, wherein the protrusion of the fastening plate is coupled to an end portion of the gasket. 7.The secondary battery of claim 6, wherein the electrode terminal includes a flange portion extending in a direction parallel to the upper surface of the cover plate, and wherein the protrusion of the fastening plate is outside the flange portion of the electrode terminal. 8.The secondary battery of claim 1, further comprising a holder, wherein the current collector includes a first region coupled to the electrode assembly and a second region extending from the first region and coupled to the electrode terminal, and wherein the holder is coupled to a lower portion of the second region of the current collector. 9.The secondary battery of claim 8, wherein the holder extends in a direction parallel to the upper surface of the cover plate along the second region. 10.The secondary battery of claim 8, further comprising an insulating plate between the electrode assembly and the cover plate, wherein the holder is coupled to the insulating plate. ​

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