Patent Description:
Unlike a primary battery that is not designed to be recharged, a secondary battery is designed to be a rechargeable and dischargeable battery. A low-capacity secondary battery including one single cell packaged in the form of a pack may be used for various portable small-sized electronic devices, such as cellular phones or camcorders. In addition, a high-capacity secondary battery in which several tens of cells are connected in a battery pack is widely used as a power source for motor drives, such as those in hybrid vehicles or electric vehicles.

When such a secondary battery is mounted in an electronic device or vehicle, the secondary battery is exposed to vibration or shock due to external environments. In addition, when the secondary battery is repeatedly subject to vibration or shock, the inside of the secondary battery may be affected, causing malfunction. Accordingly, it is desirable to provide a structure for alleviating vibration or shock applied to the secondary battery. For example, <CIT> discloses a secondary battery which comprises: an electrode assembly; a case in which the electrode assembly is accommodated; a cap plate which is coupled to the case and seals the electrode assembly; a terminal which is connected to the electrode assembly and exposed through the cap plate; and a charging member which is interposed between the cap plate and the terminal, wherein the charging member may comprise a conductive member interposed between the cap plate and the terminal, and an insulating member interposed between the conductive member, the cap plate, and the terminal. <CIT>, forming the basis for the preamble of claim <NUM>, describes a secondary battery having a cathode terminal-integrated cap plate, which prevents the occurrence of weld defects during welding of a bus bar. <CIT> relates to secondary battery including a case having an upper opening and an internal cavity, an electrode assembly disposed within the internal cavity of the case, a cap plate coupled to the case and sealing the upper opening, a collector plate coupled to the electrode assembly, a collector terminal coupled to the collector plate, the collector terminal including a rivet portion and terminal portion above a top surface of the cap plate, and a terminal plate positioned above the cap plate and coupled to the rivet portion of the collector terminal. <CIT> describes a rechargeable battery includes: an electrode assembly in a case; a cap plate coupled to an opening of the case; a rivet electrically connected to the electrode assembly, the rivet including: a first rivet flange; and a second rivet flange; and a gasket between the rivet flange and the cap plate, the gasket including: a first gasket flange configured to be coupled with the first rivet flange; and a second gasket flange configured to be coupled with the second rivet flange.

According to embodiments of the present disclosure, a secondary battery is provided that has increased coupling force of electrode terminals and increased internal space efficiency.

According to an embodiment of the present disclosure, a secondary battery includes: a case having an internal space; an electrode assembly accommodated in the internal space of the case; a current collector plate electrically connected to the electrode assembly; and a cap assembly. The cap assembly includes: a cap plate sealing the case; an electrode terminal coupled to the current collector and extending through the cap plate; and a gasket between the electrode terminal and the cap plate. The gasket has a flange portion, and the flange portion of the gasket is between an upper surface of the cap plate and the electrode terminal. The electrode terminal includes a flange portion, and the flange portion of the gasket extends in a longitudinal direction from the upper surface of the cap plate along the flange portion of the electrode terminal. The secondary battery further includes a fastening plate between the gasket and the cap plate which covers at least of a portion of the gasket and the cap plate.

The electrode terminal may include a flange portion extending in a horizontal direction of an upper portion of the cap plate, and the flange portion of the electrode terminal may be coupled to an upper surface of the gasket. That is, the lower portion of the flange portion of the electrode terminal may be in contact with an upper surface of the gasket.

The flange portion may extend along a periphery of a body of the electrode terminal, and the electrode terminal may be affixed to the cap plate by the flange portion of the electrode assembly and the gasket extending around a lower portion of the body.

The fastening plate may have a terminal hole through which the electrode terminal passes and a protrusion protruding from an inner side of the terminal hole, and the protrusion of the fastening plate may be coupled to an end of the gasket.

The electrode terminal may include a flange portion extending in a horizontal direction of an upper portion of the cap plate, and the protrusion of the fastening plate may be located outside the flange portion of the electrode terminal. That is, in a plain view on a plain parallel to an upper surface of the cap plate, the protrusion of the fastening plate and the flange portion of the electrode terminal do not overlap.

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

The retainer may extend in a longitudinal direction of the electrode assembly along the second region.

The secondary battery may include an insulating plate between the electrode assembly and the cap plate, and the retainer may be coupled to the insulating plate.

The electrode terminal may comprise a first rivet portion provided at a lower end of a main body of the electrode terminal and coupled to the second region of the current collector plate.

A terminal plate may be provided on an upper portion of the cap plate. The electrode terminal may further comprise a second rivet portion provided at an upper end of the main body of the electrode terminal to be coupled to the terminal plate.

Embodiments of the present disclosure will now be described in detail such that they may be easily implemented by a person of ordinary skill in the technical field to which the present disclosure belongs with reference to the drawings.

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

In the figures, dimensions of the various elements, layers, etc. may be exaggerated for clarity of illustration. The same reference numerals designate the same elements. Further, the use of "may" when describing embodiments of the present disclosure relates to "one or more embodiments of the present disclosure. " Expressions, such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art.

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 sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments.

Spatially relative terms, such as "beneath," "below," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the term "below" may encompass both an orientation of above and below. The device may be otherwise oriented (rotated <NUM> degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure. It will be further understood that the terms "includes," "including," "comprises," and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

<FIG> is a perspective view of a secondary battery according to an embodiment of the present disclosure. <FIG> is an exploded perspective view of the secondary battery shown in <FIG>. <FIG> is a cross-sectional view taken along the line A-A' of <FIG>. <FIG> is a partially exploded perspective view showing the portion B of <FIG>.

Referring to <FIG>, the secondary battery <NUM> according to an embodiment of the present disclosure includes an electrode assembly <NUM>, a current collector plate <NUM>, a retainer <NUM>, an insulating plate <NUM>, a cap assembly <NUM>, and a case <NUM>.

The electrode assembly <NUM> is formed by stacking or winding a laminate of a first electrode plate, a separator, and a second electrode plate formed in thin plate shapes or film shapes. The first electrode plate may act as a negative electrode, and the second electrode plate may act as a positive electrode. Of course, in other embodiments, the first electrode plate and the second electrode plate may have any polarities as long as they have different polarities from each other.

The first electrode plate is formed by coating a first electrode active material, such as graphite or carbon, on a first electrode current collector made of a metal foil, such as copper or nickel, and includes a first electrode uncoated portion that is a region to which the first active material is not applied. The first electrode uncoated portion provides a passage for current flow between the first electrode plate and the outside. The material of the first electrode plate is not limited to the above examples.

In addition, the uncoated portion of the first electrode plate may form a first current collection tab <NUM>. A plurality of first current collection tabs <NUM> may be formed to protrude from the first electrode plate. In an embodiment having a stacked structure, a shown in <FIG>, the first current collection tabs <NUM> may be formed to protrude from the first electrode plate in a direction (e.g., a predetermined direction) to overlap at one side. In addition, in an embodiment having a winding (or wound) structure, the first current collection tabs <NUM> may be formed by arranging uncoated portions at a distance (e.g., a pre-calculated distance) from the first electrode plate so that the first current collection tabs <NUM> protrude from the same area after being wound to overlap. For instance, the first current collection tabs <NUM> and the second current collection tabs <NUM> may be formed as a cusp extending from a lateral portion of the electrode assembly <NUM>. Because the first current collection tabs <NUM> are integrally formed with the first electrode plates and are drawn out from (e.g., extend from) each of the first electrode plates, the current collection efficiency from the electrode assembly <NUM> can be increased. However, in other embodiments, the first current collection tabs <NUM> may be formed by using a separate member different from the first electrode plates.

The second electrode plate is formed by coating a second electrode active material, such as a transition metal oxide, on a second electrode current collector made of a metal foil, such as aluminum, and may include a second electrode uncoated portion that is a region to which the second active material is not applied. In addition, a second current collection tab <NUM> may be formed from the uncoated portion of the second electrode plate to correspond to the first current collection tab <NUM>. Accordingly, the second current collection tab <NUM> may also have a multi-tap structure, similar to the first current collection tab <NUM>. Further, the material of the second electrode plate is not limited to the above examples.

The separator is positioned between the first electrode plate and the second electrode plate to prevent a short circuit therebetween and to enable movement of lithium ions. The separator may be made of polyethylene, polypropylene, or a composite film of polyethylene and polypropylene. The material of the separator is not limited to the above examples.

The electrode assembly <NUM> may be substantially accommodated in the case <NUM> together with an electrolyte. The electrolyte may include a lithium salt, such as LiPF<NUM> or LiBF<NUM>, in an organic solvent, such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC). The electrolyte may be in a liquid, solid, or gel form.

The first current collection tab <NUM> and the second current collection tab <NUM> are electrically connected to the current collector plate <NUM>. A pair of current collector plates <NUM> may be provided and may be electrically connected to the first current collection tab <NUM> and the second current collection tab <NUM> of the electrode assembly <NUM>, respectively. The current collector plates <NUM> are respectively connected to the first current collection tab <NUM> and the second current collection tab <NUM> of the electrode assembly <NUM>. For example, a first current collector plate <NUM> is in contact with the first current collection tab <NUM> and a second current collector plate <NUM> is in contact with the second current collection tab <NUM> protruding from the side portion of the electrode assembly <NUM>, and, in this state, the first current collector plate <NUM> and the first current collection tab <NUM> can be coupled to each other, by a process such as welding. In the same way, the second current collector plate <NUM> and the second current collection tab <NUM> can also be coupled to each other, by a process such as welding. Accordingly, the first and second current collector plates <NUM> may be electrically connected to each of the first current collection tab <NUM> and the second current collection tab <NUM>. For example, the first current collector plate <NUM> electrically connected to the first current collection tab <NUM> may have a negative polarity, and the second current collector plate <NUM> electrically connected to the second current collection tab <NUM> may have a positive polarity.

Each of the current collector plates <NUM> may include a first region (e.g., a first portion) <NUM> and a second region (e.g., a second portion) <NUM>. In some embodiments, the first regions <NUM> may be arranged in a direction parallel to the first current collection tab <NUM> or the second current collection tab <NUM> of the electrode assembly <NUM>, and in this state, the first current collection tab <NUM> and the second current collection tab <NUM> may be welded thereto. In addition, the second regions <NUM> may be coupled to the first regions <NUM> by a process, such as welding, on the upper portion (e.g., upper end or upper area) of the first region <NUM>. The second region <NUM> may extend perpendicularly to the first region <NUM>. However, in some embodiments, the first region <NUM> and the second region <NUM> may be provided integrally.

Accordingly, the current collector plate <NUM> having the first region <NUM> with the second region <NUM> coupled thereto may have the same polarity as the corresponding one of the first current collection tab <NUM> and the second current collection tab <NUM>, which is connected thereto.

The retainer <NUM> may be coupled to a lower portion of the second region <NUM> of the current collector plate <NUM>. The retainer <NUM> is made of an electrical insulator and may couple the current collector plate <NUM> to the insulating plate <NUM> located thereon. To this end, the retainer <NUM> may have a hook <NUM> protruding upwardly in at least two areas and may be fastened to the insulating plate <NUM> by the hook <NUM>. Accordingly, the second region <NUM> of the current collector plate <NUM> is fixed to the insulating plate <NUM>, and the electrode assembly <NUM> coupled to the first region <NUM> of the current collector plate <NUM> may remain coupled to the insulating plate <NUM>.

The insulating plate <NUM> may extend parallel to an upper portion of the electrode assembly <NUM> in a horizontal direction. The insulating plate <NUM> may be made of an insulating polymer, such as polypropylene (PP), polyethylene (PE), or polystyrene (PS). The insulating plate <NUM> may have a vent hole (e.g., a vent opening) <NUM> located at substantially the center thereof in the horizontal direction of the electrode assembly <NUM>, an injection hole (e.g., an injection opening) <NUM> formed to be spaced apart from one side of the vent hole <NUM>, and terminal holes (e.g., terminal openings) <NUM> located at both ends of the electrode assembly <NUM> in the horizontal direction.

In addition, the insulating plate <NUM> may have a hook fastening groove <NUM> formed in a part of the side surface <NUM> to be fastened to the hook <NUM> of the retainer <NUM>, as described above. For example, the hook <NUM> of the retainer <NUM> protrudes upwardly through the hook fastening groove <NUM> in the insulating plate <NUM>, and the lower end of the hook <NUM> may be caught on the upper surface of the insulating plate <NUM>, thereby maintaining a fastened state.

The cap assembly <NUM> is formed on the insulating plate <NUM> and is coupled to the case <NUM> to seal the case <NUM>. The cap assembly <NUM> includes a cap plate <NUM>, a fastening plate <NUM>, a gasket <NUM>, an electrode terminal <NUM>, and a terminal plate <NUM>.

The cap plate <NUM> may be formed in a plate shape, may be coupled to an opening of the case <NUM>, and may be formed of the same material as the case <NUM>. The cap plate <NUM> may be coupled to the case <NUM> by, for example, laser welding. The cap plate <NUM> may be electrically independent (e.g., electrically neutral) or may be electrically connected to either the first current collection tab <NUM> or the second current collection tab <NUM> in various embodiments. For example, the cap plate <NUM> may be electrically connected to the second current collection tab <NUM>, and in such an embodiment, the cap plate <NUM> and the case <NUM> have the same polarity (e.g., the positive polarity). In other embodiments, the cap plate <NUM> may be electrically connected to the first current collection tab <NUM>.

A vent hole (e.g., a vent opening) 151a may be formed at approximately the center of the cap plate <NUM>, and a safety vent 151b formed to have a relatively small thickness, compared to other regions, may be formed inside the vent hole 151a. If the internal pressure of the case <NUM> becomes higher than a rupture pressure, the safety vent 151b ruptures (e.g., bursts) to prevent the secondary battery <NUM> from exploding.

In addition, an electrolyte injection hole (e.g., an electrolyte injection opening) 151c for injecting an electrolyte may be formed at one side of the cap plate <NUM>. The electrolyte may be injected into the case <NUM> through the electrolyte injection hole 151c, and the electrolyte injection hole 151c may be then sealed by a plug.

In addition, terminal holes (e.g., terminal openings) 151d through which the electrode terminals <NUM> pass may be formed at both sides of the cap plate <NUM>, and a gasket <NUM> and an electrode terminal <NUM> may be coupled to the terminal holes 151d, respectively.

In addition, fastening protrusions 151e formed around the terminal holes 151d may be further formed on both sides of the cap plate <NUM>, and regions at where the terminal holes 151d and the fastening protrusion 151e are present may be lower than the cap plate <NUM> through an entirely engraved region (e.g., by being in a recessed region of the cap plate <NUM>). Accordingly, the position of the fastening plate <NUM> can be fixed by (or within) the engraved region and the fastening protrusion 151e in the region.

A pair of fastening plates <NUM> may be provided and may be respectively coupled to both sides of the upper surface of the cap plate <NUM>. The fastening plates <NUM> may be positioned in the engraved region formed in the upper surface of the cap plate <NUM> and may be coupled to the fastening protrusion 151e of the cap plate <NUM> by a fastening protrusion 152a. In addition, each of the fastening plates <NUM> may accommodate the gasket <NUM> and the electrode terminal <NUM> through the terminal holes formed therein. In addition, the fastening plate <NUM> may further include a protrusion 152b protruding a length (e.g., a predetermined length) from inside the terminal hole, and the protrusion 152b may press the gasket <NUM>, to be described later, from the upper portion to fix the position of the gasket <NUM>. The fastening plates <NUM> on left side and right side in <FIG> can be one among insulating/insulating, conductive/insulating, or insulating/conductive type.

The gasket <NUM> may be made of an insulating material and may be coupled to the upper portion of the fastening plate <NUM> to seal an area between the electrode terminal <NUM> and the fastening plate <NUM>. The gasket <NUM> prevents external moisture from penetrating into the secondary battery <NUM> and prevents the electrolyte contained in the secondary battery <NUM> from leaking to the outside.

The gasket <NUM> has a flange portion 153a at an upper end thereof, and the flange portion 153a may extend from an upper surface of the gasket <NUM> in the horizontal direction. Accordingly, the electrolyte may not leak between the electrode terminal <NUM> and the cap plate <NUM>.

In addition, the flange portion 153a can be fixed by pressing an edge of the upper surface thereof by the protrusion 152b formed in the terminal hole of the fastening plate <NUM>. In addition, the flange portion 153a may be fixed by pressing a portion of the upper surface of the flange portion 153a other than the edge being in contact with the protrusion 152b by the electrode terminal <NUM>. Accordingly, the flange portion 153a and the gasket <NUM> having the flange portion 153a may be fixed between the electrode terminal <NUM> and the cap plate <NUM>.

The gasket <NUM> is positioned outside the cap plate <NUM> when viewed with respect to the cap plate <NUM>. That is, the upper portion of the gasket <NUM> is extended above a surface of the cap plate <NUM>. Accordingly, because the internal space of the secondary battery partitioned by the cap plate <NUM> and the case <NUM> is increased, the battery capacity can be increased.

The electrode terminal <NUM> may be located within a hole (e.g., an opening) formed in the gasket <NUM>, and accordingly, the electrode terminal <NUM> may be sequentially coupled to the fastening plate <NUM>, the cap plate <NUM>, the insulating plate <NUM>, and the second region <NUM> of the current collector plate <NUM>, positioned below the electrode terminal <NUM>, in that order. The electrode terminal <NUM> may include a first rivet portion 154a provided at the lower end of the main body of the electrode terminal <NUM> and coupled to the respective second region <NUM> of the current collector plate <NUM>, a flange portion 154b positioned at an approximate central height of the main body to be coupled to the protrusion 152b of the fastening plate <NUM>, and a second rivet portion 154c provided on the upper end of the main body to be coupled to the terminal plate <NUM>.

The first rivet portion 154a may be formed to protrude along the lower end of the main body of the electrode terminal <NUM>. The first rivet portion 154a may be in contact with the second region <NUM> of the current collector plate <NUM> and may be deformed through riveting to be fastened to the second region <NUM>. Accordingly, through the first rivet portion 154a, the electrode terminal <NUM> may have the same polarity as that of the current collector plate <NUM>.

The flange portion 154b extends in the horizontal direction from the approximate center of the electrode terminal <NUM>. when the first rivet portion 154a passes through the terminal hole 151d in the cap plate <NUM> together with the gasket <NUM> and is coupled thereto, the flange portion 154b presses on the upper surface of the flange portion 153a of the gasket <NUM>. Accordingly, the flange portion 154b can fix the gasket <NUM> and increase a sealing force. In addition, the coupling area between the flange portion 154b and the gasket <NUM> is located outside the cap plate <NUM>. Accordingly, the internal space in the case <NUM> may be increased, thereby increasing battery capacity and increasing efficiency.

The second rivet portion 154c may protrude upwardly from the main body of the electrode terminal <NUM> and may be riveted to the terminal plate <NUM> positioned at the uppermost portion. In addition, a separate welding process can be performed along the edge of the riveted second rivet portion 154c.

One terminal plate <NUM> may be coupled to each of the electrode terminals <NUM> protruding to (or protruding from) an upper portion of the cap plate <NUM>, respectively, through the terminal holes 151d in the cap plate <NUM>. After the terminal plate <NUM> is coupled to the respective electrode terminal <NUM>, the second rivet portion 154c of the electrode terminal <NUM> is riveted or welded together thereto, thereby fixing the electrode terminal <NUM> to the terminal plate <NUM>.

The case <NUM> may be made of a conductive metal, such as aluminum, an aluminum alloy, or nickel-plated steel, and has a substantially hexahedral shape having an opening through which the electrode assembly <NUM> can be inserted and seated. The cap plate <NUM> is coupled to the case <NUM> at the opening therein to seal the case <NUM>. The inner surface of the case <NUM> may be insulated to prevent an electrical short from occurring therein. In addition, in some embodiments, one electrode of the electrode assembly <NUM> may be electrically connected to the case <NUM> through the cap plate <NUM>. In such embodiments, an electrical short circuit inside the case <NUM> is prevented by the inner insulation treatment. In such embodiments, the case <NUM> may act as a positive electrode.

As described above, the secondary battery according to embodiments of the present disclosure includes a gasket coupled to an electrode terminal, and because a fastening portion between the electrode terminal and the gasket is positioned outside the cap plate, the internal space in the case is increased, thereby increasing battery capacity.

Claim 1:
A secondary battery (<NUM>) comprising:
a case (<NUM>) having an internal space;
an electrode assembly (<NUM>) accommodated in the internal space of the case (<NUM>);
a current collector plate (<NUM>) electrically connected to the electrode assembly (<NUM>); and
a cap assembly (<NUM>) comprising:
a cap plate (<NUM>) sealing the case (<NUM>);
an electrode terminal (<NUM>) coupled to the current collector plate (<NUM>) and extending through the cap plate (<NUM>); and
a gasket (<NUM>) between the electrode terminal (<NUM>) and the cap plate (<NUM>) and having a flange portion (153a), the flange portion (153a) of the gasket (<NUM>) being between an upper surface of the cap plate (<NUM>) and the electrode terminal (<NUM>), characterised by
a fastening plate (<NUM>) between the gasket (<NUM>) and the cap plate (<NUM>) and covering at least of a portion of the gasket (<NUM>) and the cap plate (<NUM>),
wherein the electrode terminal (<NUM>) comprises a flange portion (154b) extending in a horizontal direction of an upper surface of the cap plate (<NUM>).