Patent Description:
A secondary battery includes an electrode assembly, a case for accommodating the electrode assembly and an electrolyte, and a cap assembly coupled to an upper opening of the case to seal the case. The cap assembly is electrically connected to the electrode assembly to electrically connect an external structure (e.g., an external device) and the electrode assembly.

A cylindrical secondary battery generally has a structure in which a can having a negative polarity and a cap assembly having a positive polarity are insulated from each other by a gasket. In the case of a battery module including a plurality of cylindrical secondary batteries connected to each other, bus bars must be connected to the upper and lower portions of the secondary batteries, the structure and/or configuration of the battery module becomes complicated and the process time is prolonged.

The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure, and therefore, it may contain information that does not constitute prior art.

<CIT> describes a cylindrical high-capacity sealed storage cell having a terminal at one end which is made of aluminum, wherein: the one end includes an aluminum cover adapted to be brought into contact with an external electrical connecting part by a clamping structure which is at least in part under the cover and co-operates with an external assembly mechanism, the clamping structure being made from a material selected from the group consisting of stainless steel, nickel-plated steel, copper, and brass; and the cover of the cell is sealed by a metal sealing cap under the cover.

<CIT> describes a battery including an electrode unit housed in a battery can and which generates electricity which can be taken out of the battery via a pair of negative and positive electrode terminals, wherein a terminal assembly is installed in the battery, a current collector plate is connected to an edge of an electrode of the electrode unit for connecting the electrode unit to the terminal assembly, and one or more than one connecting piece which is protrusively formed on a surface of the current collector plate is welded and secured to a base portion of the terminal assembly.

Embodiments of the present disclosure provide a secondary battery which can be easily compressed with an insulating member due to a protrusion provided in a terminal hole in a case, thereby improving sealing force between the case and a terminal.

In addition, embodiments of the present disclosure provide a secondary battery in which both a negative electrode and a positive electrode are provided at the same side, and thus, when a plurality of secondary batteries are electrically connected through a bus bar, the secondary batteries are connected at only one side, thereby simplifying a bus bar connection structure.

A secondary battery according to the present disclosure, is as defined in claim <NUM>.

The terminal may include a head outside the case and a fastening part coupled to an inner surface of the case through the terminal hole in the case.

The fastening part may have a larger diameter than the terminal hole in the case.

The insulation member may have a diameter gradually increasing toward the inside of the case according to a shape of the fastening part in a region where the terminal is inserted into the inside of the case.

The protrusion may protrude toward the inside or the outside of the case.

The secondary battery may further include an insulation member between the terminal and the case. The insulation member may be coupled around an outer peripheral surface of the protrusion.

The protrusion may be compressed with the insulation member according to a shape of the terminal on the outside of the insulation member.

The terminal may have an electrical polarity different from that of the case.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

Embodiments of the present disclosure are provided to more completely explain the present disclosure to those skilled in the art, and the following embodiments may be modified in various other forms. The present disclosure, however, may be embodied 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 the aspects and features of the present disclosure to those skilled in the art.

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 illustrating a secondary battery <NUM> according to an embodiment of the present disclosure, <FIG> is a cross-sectional view of the secondary battery <NUM> shown in <FIG>, and <FIG> is a partially exploded cross-sectional view of the portion <NUM> in <FIG>.

As shown in <FIG>, the secondary battery <NUM> may include a case (e.g., a can) <NUM>, an electrode assembly <NUM> accommodated in the case <NUM>, a terminal <NUM> coupled at a terminal hole (e.g., a terminal opening) 111a in one end of the case <NUM>, and a cap plate <NUM> sealing an opening 110a in another end (e.g., an opposite end) of the case <NUM>.

The case <NUM> has a circular upper surface portion <NUM> and a side portion <NUM> extending a length (e.g., a predetermined length) downwardly from the edge of the upper surface portion <NUM>. The upper surface portion <NUM> and the side portion <NUM> of the case <NUM> may be formed integrally. An opening 110a may be provided in a lower portion (e.g., at a lower end) of the case <NUM>. Hereinafter, for convenience of description, the case <NUM> will be shown and described as having the upper surface portion <NUM> and the side portion <NUM> and having the opening 110a formed at the lower portion thereof. However, in the case <NUM>, the position of the opening 110a may vary in various manners by rotation. For example, the case <NUM> may have the opening 110a at the upper portion thereof and may have an upper surface portion <NUM> formed at the lower portion with the side portion <NUM> extending upwardly therefrom. In addition, in a side-lying arrangement, the upper surface portion <NUM> may face one side and the opening 110a may face the other side. The case <NUM> may have the opening 110a at one end thereof, and a terminal hole 111a may be provided in a surface opposite to the opening 110a.

The circular upper surface portion <NUM> may have a flat circular plate shape and may have a terminal hole (e.g., a terminal opening) 111a penetrating the center thereof. In addition, a protrusion 111c may be provided on the upper surface portion <NUM> to face (e.g., to protrude toward) the inside or the outside of the case <NUM> along the edge of the terminal hole 111a. The protrusion 111c may protrude upwardly from the upper surface of the upper surface portion <NUM> or may protrude downwardly from the lower surface of the upper surface portion <NUM>. The protrusion 111c may be shaped to correspond to the terminal hole 111a. For example, the protrusion 111c may have a circular ring shape corresponding to the shape of the terminal hole 111a and may protrude toward the inside or outside of the case <NUM>. The protrusion 111c may be formed when processing (e.g., forming) the terminal hole 111a in the case <NUM>. The terminal hole 111a may be formed by processing through a piercing punch of a press mold.

As an embodiment, as shown in <FIG>, when the terminal hole 111a is formed by processing from the inside to the outside of the case <NUM>, the protrusion 111c may be formed in the outward direction of (or from) the case <NUM>. As another embodiment, as shown in <FIG>, when the terminal hole 111a is formed by machining from the outside to the inside of the case <NUM>, the protrusion 111c may be formed in the inward direction of the case <NUM>. The terminal <NUM> may be inserted and coupled at the terminal hole 111a in the case <NUM> as described above. In addition, an insulation member 111b for sealing and electrical insulation may be interposed between the terminal hole 111a and the terminal <NUM>.

The insulation member 111b may prevent contact between the terminal <NUM> and the case <NUM> and, thus, the terminal <NUM> and the case <NUM> may be electrically separated (or electrically isolated). The terminal hole 111a in the case <NUM> may be sealed by the insulation member 111b. The insulation member 111b may be made of a resin material, such as polyethylene (PE), polypropylene (PP), or polyethylene terephthalate (PET).

In the secondary battery <NUM>, the electrode assembly <NUM> may be inserted into the case <NUM> through the opening 110a in the case <NUM> during a manufacturing process. The electrode assembly <NUM> may be inserted into the case <NUM> while the opening 110a faces upwardly. After the electrode assembly <NUM> is inserted into the case <NUM>, the cap plate <NUM> may be coupled to the opening 110a to seal the inside of the case <NUM>.

The case <NUM> may be made of steel, a steel alloy, aluminium, an aluminium alloy, or an equivalent thereof, but the material thereof is not limited thereto. In addition, to prevent the electrode assembly <NUM> from being separated to the outside, the case <NUM> may have a beading part (e.g., a bead) <NUM> inwardly recessed at the upper side and a crimping part (e.g., a crimped end) <NUM> inwardly bent at the lower side with respect to the cap plate <NUM>.

After the electrode assembly <NUM> is inserted through the opening 110a at the lower side of the case <NUM>, the beading part <NUM> may prevent the electrode assembly <NUM> from being separated from the case <NUM>.

The electrode assembly <NUM> may include a first electrode plate <NUM>, a second electrode plate <NUM>, and a separator <NUM>. The first electrode plate <NUM> may be a positive electrode plate, and the second electrode plate <NUM> may be a negative electrode plate. In other embodiments, however, the reverse is possible. Hereinafter, for convenience of description, an embodiment in which the first electrode plate <NUM> is a positive electrode plate and the second electrode plate <NUM> is a negative electrode plate will be described.

The first electrode plate <NUM> may have a positive electrode active material, made of a transition metal oxide, coated on at least one surface of a plate-shaped metal foil, made of, for example, aluminium (Al). In addition, the first electrode plate <NUM> may have a positive electrode uncoated portion, on which the positive electrode active material is not coated, at an upper end thereof. The positive electrode uncoated portion may protrude upwardly from the electrode assembly <NUM>. For example, the positive electrode uncoated portion of the first electrode plate <NUM> may protrude upwardly above the second electrode plate <NUM> and the separator <NUM>.

The second electrode plate <NUM> may have a negative electrode active material, made of graphite or carbon, coated on at least one surface of a plate-shaped metal foil, made of, for example, copper (Cu) or nickel (Ni). In addition, the second electrode plate <NUM> may have a negative electrode uncoated portion, on which the negative electrode active material is not coated, at a lower end thereof. The negative electrode uncoated portion may protrude downwardly from the electrode assembly <NUM>. For example, the second electrode plate <NUM> may protrude downwardly below than the first electrode plate <NUM> and the separator <NUM>.

The separator <NUM> may be made of polyethylene (PE) or polypropylene (PP), but the present disclosure is not limited thereto. The separator <NUM> may prevent an electric short between the first electrode plate <NUM> and the second electrode plate <NUM> while allowing lithium ions to move therebetween.

After the first electrode plate <NUM>, the second electrode plate <NUM>, and the separator <NUM> are stacked, the electrode assembly <NUM> is wound from (or about) a winding tip to have a substantially cylindrical shape. In the electrode assembly <NUM>, the positive electrode uncoated portion may upwardly protrude from the first electrode plate <NUM> and the negative electrode uncoated portion may downwardly protrude from the second electrode plate <NUM>.

The first current collector plate <NUM> may be a circular metal plate shaped to correspond to the upper surface of the electrode assembly <NUM>. The planar size of the first current collector plate <NUM> may be the same as or smaller than the size (e.g., the planar size or surface area) of the upper surface of the electrode assembly <NUM>. The first current collector plate <NUM> may be made of aluminium (Al). The first current collector plate <NUM> may be fixed and electrically connected to the first electrode plate <NUM>, which is exposed at the upper portion of the electrode assembly <NUM>, by welding when the lower surface of the first current collector plate <NUM> is in contact with the upper surface of the electrode assembly <NUM>. The first current collector plate <NUM> acts as a passage for current flow between the first electrode plate <NUM> of the electrode assembly <NUM> and the terminal <NUM>.

The second current collector plate <NUM> may have a circular flat portion <NUM> corresponding to the lower surface of the electrode assembly <NUM> and an extending portion <NUM> extending downwardly from the edge of the flat portion <NUM>. The upper surface of the flat portion <NUM> may be in contact with the lower surface of the electrode assembly <NUM>. The upper surface of the flat portion <NUM> may be fixed and electrically connected to the second electrode plate <NUM>, which is exposed at the lower portion of the electrode assembly <NUM>, by welding while in contact with the lower surface of the electrode assembly <NUM>.

The extending portion <NUM> may extend downwardly from the edge of the flat portion <NUM>. The extending portion <NUM> may be in contact with and coupled to (e.g., fixed by) the beading part <NUM> of the case <NUM>. In an embodiment, the extending portion <NUM> may be coupled to the beading part <NUM> of the case <NUM> by welding while being in contact with the inner surface of the beading part <NUM> of the case <NUM>. In addition, a plurality of extending portions <NUM> may be spaced apart from each other along the edge of the flat portion <NUM>. The second current collector plate <NUM> may act as a passage for current flow between the second electrode plate <NUM> of the electrode assembly <NUM> and the case <NUM>. That is, the case <NUM> may be a negative electrode terminal.

The terminal <NUM> may be inserted into the terminal hole 111a provided in the upper surface portion <NUM> of the case <NUM> to be electrically connected to the first current collector plate <NUM>. For example, the terminal <NUM> may be a positive electrode terminal. The terminal <NUM> and the case <NUM> may have different polarities. The terminal <NUM> may be made of the same or similar material as the first current collector plate <NUM> and the first electrode plate <NUM>. A diameter of a portion of the terminal <NUM> exposed to (e.g., above) the upper portion of the case <NUM> and a diameter of a portion of the terminal <NUM> positioned inside the case <NUM> may be larger than a diameter of a portion of the terminal <NUM> positioned in the terminal hole 111a.

The terminal <NUM> may have a head <NUM> at a portion exposed to the upper portion of the case <NUM> and a fastening part <NUM> at a portion facing the electrode assembly <NUM> while being positioned inside the case <NUM>. The terminal <NUM> may be coupled at the terminal hole 111a in the case <NUM> from the outside to the inside. The head <NUM> may be outside the case <NUM>. In addition, the fastening part <NUM> may be compression-deformed (e.g., compression-molded) by riveting to be compressed while the insulation member 111b is interposed at the lower portion of the upper surface portion <NUM>. The fastening part <NUM> may have a diameter gradually increasing from the terminal hole 111a toward the inner side of (e.g., toward the inside of) the case <NUM>. In addition, the head <NUM> may be in close contact with the upper surface of the upper surface portion <NUM> with the insulation member 111b interposed therebetween.

The protrusion 111c provided in the case <NUM> may compress the insulation member 111b when the terminal <NUM> is coupled to the terminal hole 111a. For example, because the protrusion 111c presses the insulation member 111b, the bonding strength between the insulation member 111b and the case <NUM> can be improved and sealing can be facilitated. The insulation member 111b may wrap (e.g., may extend around) the outer peripheral surface of the protrusion 111c of the case <NUM>. The case <NUM> and the terminal <NUM> may be coupled by being pressed while the insulation member 111b is interposed therebetween. The insulation member 111b may prevent contact between the terminal <NUM> and the case <NUM>, which may have different polarities, and thus, the terminals <NUM> and the case <NUM> may be electrically separated from each other. In addition, the insulation member 111b may seal between the terminal hole 111a in the case <NUM> and the terminal <NUM>.

The cap plate <NUM> is a circular metal plate and may be coupled at the opening 110a in the case <NUM>. The cap plate <NUM> may be coupled at the opening 110a in the case <NUM> while a gasket <NUM> is interposed therebetween, thereby preventing the cap plate <NUM> from being electrically connected to the case <NUM>. The cap plate <NUM> is not electrically connected to the positive electrode or the negative electrode of the electrode assembly <NUM> and, thus, may not have any separate electrical polarity.

The cap plate <NUM> may be fixed while the edge of the cap plate <NUM> is positioned between the beading part <NUM> of the case <NUM> and the crimping part <NUM>. For example, the gasket <NUM> is interposed between the beading part <NUM> of the case <NUM> and the cap plate <NUM>. Thereafter, the crimping part <NUM> of the case <NUM> may be inwardly bent from the cap plate <NUM> to press the gasket <NUM>, thereby coupling the cap plate <NUM> and the case <NUM> to each other.

The cap plate <NUM> may have at least one protrusion <NUM> that protrudes downwardly. In an embodiment, the protrusion <NUM> of the cap plate <NUM> may be spaced apart from (e.g., may be offset from) the center thereof and may protrude downwardly to have a planar ring shape. In another embodiment, the protrusion <NUM> of the cap plate <NUM> may protrude downwardly to have a plurality of patterns. By including the protrusion <NUM>, the cap plate <NUM> may support (e.g., contain) the internal pressure of the case <NUM> (e.g., the cap plate <NUM> may be corrugated to increase its strength). In addition, the lower surface of the protrusion <NUM> of the cap plate <NUM> may be lower than (e.g., may protrude beyond) the lower surface of the crimping part <NUM> of the case <NUM>. Therefore, when the secondary battery <NUM> is placed on a flat surface, the protrusion <NUM> of the cap plate <NUM> may be in contact with one surface while the crimping part <NUM> of the case <NUM> may is spaced apart from the one surface. The cap plate <NUM> may have unevenness by the protrusions <NUM>, and thus, can better withstand the internal pressure even when the internal pressure of the case <NUM> increases.

A safety vent <NUM> may be formed in the cap plate <NUM> and may be configured to open (e.g., rupture) at a set pressure. The safety vent <NUM> may be a region of the cap plate <NUM> having a smaller thickness than other regions of the cap plate <NUM>. When the internal pressure in the case <NUM> is equal to or greater than the breaking (or rupture) pressure of the safety vent <NUM>, the safety vent <NUM> is broken (e.g., ruptures or bursts) to prevent the secondary battery <NUM> from exploding. For example, when excessive internal pressure is generated inside the case <NUM>, the safety vent <NUM> may be broken to discharge the internal excessive internal pressure. The safety vent <NUM> of the cap plate <NUM> may have a planar ring shape on (or along) the protrusion <NUM>. In another embodiment, the safety vent <NUM> may be formed of a plurality of patterns. However, the shape of the safety vent <NUM> is not limited in the present disclosure.

An electrolyte injection hole (e.g., an electrolyte injection opening) 160a may be provided in an approximate center of the cap plate <NUM>. The electrolyte injection hole 160a may be sealed by a stopper <NUM> after the electrolyte is injected into the case <NUM>. The electrolyte allows lithium ions to move between the first electrode plate <NUM> and the second electrode plate <NUM>. The electrolyte may be a non-aqueous organic electrolyte that is a mixture of a lithium salt and a high-purity organic solvent. In addition, the electrolyte may be a polymer using (or including) a polymer electrolyte or a solid electrolyte, but the type of the electrolyte is not limited herein. The second current collector plate <NUM> may include a through hole provided in approximately the center thereof, and the electrolyte injected through the electrolyte injection hole 160a in the cap plate <NUM> may easily move to the electrode assembly <NUM> through the through hole in the second current collector plate <NUM>.

The gasket <NUM> may be made of a resin material, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like. The cap plate <NUM> may be sealed to the case <NUM> by pressing the gasket <NUM> therebetween and may prevent the cap plate <NUM> from being separated from the case <NUM>.

Because the secondary battery <NUM> includes both a negative electrode terminal and a positive electrode terminal at the upper surface thereof, when a plurality of secondary batteries <NUM> are electrically connected through a bus bar, the secondary batteries <NUM> may be connected at only the upper surface, thereby simplifying a bus bar connection structure.

As described above, in the secondary battery according to embodiments of the present disclosure, an insulating member arranged in a terminal hole in a case can be easily compressed, thereby improving sealing force between the case and a terminal in the terminal hole.

Claim 1:
A secondary battery comprising:
an electrode assembly (<NUM>);
a case (<NUM>) accommodating the electrode assembly (<NUM>), the case having an opening (110a) at a first end sized to accommodate the electrode assembly (<NUM>) and a terminal hole (111a) at a second end opposite to the first end;
a first current collector plate (<NUM>) coupled to the electrode assembly (<NUM>);
a terminal (<NUM>) electrically coupled to the first current collector plate (<NUM>) and extending through the terminal hole (111a) in the case (<NUM>); and
a cap plate (<NUM>) sealing the opening of the case (<NUM>); and
an insulation member (111b) between the terminal (<NUM>) and the case (<NUM>),
wherein the case (<NUM>) comprises a protrusion (111c) that protrudes in one direction along an edge of the terminal hole, towards the inside of the case (<NUM>) or towards the outside of the case (<NUM>), and
wherein the insulation member (111b) is coupled around an outer peripheral surface of the protrusion (111c).