Rechargeable battery including first and second covers

A rechargeable battery including an electrode assembly including a first electrode and a second electrode; a case having a space in which the electrode assembly is located; a cap plate coupled with the case; a terminal coupled to the electrode assembly through a current collecting tap, and protruding through the cap plate to an outside of the case; a first cover in which a lower portion of the terminal is located; and a second cover in which an upper portion of the current collecting tap is located, the second cover being coupled with the first cover to secure the terminal and the current collecting tap.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2011-0105432, filed in the Korean Intellectual Property Office on Oct. 14, 2011, the entire contents of which are incorporated herein by reference.

BACKGROUND

An aspect of the described technology relates generally to a rechargeable battery, and more particularly, to a terminal connection portion of a rechargeable battery.

2. Description of Related Art

A rechargeable battery is a battery that can be charged and discharged, unlike a primary battery that is not designed to be recharged. A rechargeable battery having a relatively low capacity may be used in a portable electronic device, such as, a mobile phone, a laptop computer, or a camcorder, and a rechargeable battery having a relatively large capacity may be used as, for example, a power supply for driving a motor in an electric vehicle, a hybrid electric vehicle, and the like.

A rechargeable battery that uses a non-aqueous electrolyte (electrolytic solution) having a relatively high energy density may be configured in a large capacity battery module, in which a plurality of rechargeable batteries are coupled in series in order to be used to drive devices requiring a relatively large level of power, for example, electric vehicle motors.

Further, one battery module may include a plurality of rechargeable batteries that are coupled in series. The rechargeable battery may be formed in cylindrical or angular shapes.

A terminal of a rechargeable battery may have a relatively complicated lower structure that is coupled to an electrode assembly; a relatively complicated work process may accompany the installation of the terminal. In addition, if the electrolytic solution infiltrates into gaps of lower structures of the terminal, an external short-circuit may occur by coupling the terminal and the cap plate.

SUMMARY

An aspect of the described technology is direct to the assembly and/or safety of a rechargeable battery.

An exemplary embodiment of the present invention provides a rechargeable battery including an electrode assembly including a first electrode and a second electrode; a case housing the electrode assembly; a cap plate coupled with the case; a terminal electrically coupled to the electrode assembly through a current collecting tap, and protruding through the cap plate to an outside of the case; a first cover in which a lower portion of the terminal is located; and a second cover in which an upper portion of the current collecting tap is located, the second cover being coupled with the first cover to secure the terminal and the current collecting tap.

The first cover may be coupled with the second cover by being inserted thereinto.

The rechargeable battery may further include a gasket, and the terminal may include a terminal flange and a terminal pillar protruding from the terminal flange to the outside of the case. The gasket may include a lower insulating portion in which the terminal flange is located and an upper insulating portion that surrounds the terminal pillar and protrudes upwardly.

The first cover may have a hole, and a portion of the gasket may be located in the first cover. The upper insulating portion of the gasket may protrude through the hole. The terminal may further include a terminal protrusion protruding from the terminal flange along a periphery of the terminal pillar. The gasket may further include a groove in which the terminal protrusion is disposed, and a step portion on an opposite side of the groove. The step portion may protrude through the hole of the first cover and may contact a lower surface of the cap plate.

The current collecting tap may include a fuse portion having a smaller cross-section than its surroundings. At least one of the first cover or the second cover may include a fuse protrusion protruding into the fuse portion.

The second cover may include protection protrusions protruding to an outside of the current collecting tap, the current collecting tap being located between the protection protrusions.

The second cover may surround the upper portion of the current collecting tap and sidewalls of the first cover.

The first cover may surround sidewalls of the second cover.

A sealant may be between the first cover and the second cover.

The first cover may include a protrusion inserted into a groove on the cap plate.

According to an aspect of embodiments of the present invention, assembly and safety of a rechargeable battery may be improved by integrating a terminal and a current collector.

DETAILED DESCRIPTION

Hereinafter, aspects of the present invention will be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings and description, like reference numerals designate like elements throughout the specification. Throughout the specification, when a first element is referred to as being “on” or “coupled to” a second element, the first element may be directly “on” or “coupled to” the second element, or indirectly “on” or “coupled to” the second element via one or more intervening elements.

FIG. 1is a perspective view that illustrates a rechargeable battery according to a first exemplary embodiment of the present invention, andFIG. 2is a cross-sectional view that is taken along the line II-II ofFIG. 1.

Referring toFIGS. 1 and 2, the rechargeable battery101according to the first exemplary embodiment of the present invention includes an electrode assembly10that is wound with a separator13interposed between a positive electrode (first electrode)11and a negative electrode (second electrode)12, a case26housing (e.g., enclosing) the electrode assembly10, and a cap assembly30that is coupled (e.g., combined) with an opening of the case26.

The rechargeable battery101according to the first exemplary embodiment of the present invention will be described with reference to an example of an angular shaped (e.g., rectangular-shaped or hexahedral-shaped), lithium ion rechargeable battery. However, the present invention is not limited thereto, and may be applied to various types and/or shapes of batteries, such as, a lithium polymer battery or a cylindrical battery.

The positive electrode11and the negative electrode12each may include a coated region, on which an active material is coated on a current collector that is formed, for example, by a metal foil of a thin plate, and an uncoated region, on which the active material is not coated.

In one embodiment of the present invention, the positive electrode uncoated region11ais formed at one side at one end of the positive electrode11along a length direction of the positive electrode11, and the negative electrode uncoated region12ais formed at another side at one end of the negative electrode12along a length direction of the negative electrode12.

Further, the positive electrode11and negative electrode12may be arranged, e.g., wound, with a separator13that is an insulator interposed therebetween. However, aspects of the present invention are not limited thereto, and the electrode assembly10may have a structure in which the positive electrode and the negative electrode include a plurality of sheets (or plates) laminated with an insulator interposed therebetween.

The case26may have a substantially cuboid shape, and an opening may be formed at one side thereof. The cap assembly30includes a cap plate31that covers the opening of the case26, a positive electrode terminal21that protrudes outside the cap plate31and is electrically coupled to the positive electrode11, a negative electrode terminal22that protrudes outside the cap plate31and is electrically coupled to the negative electrode12, and a vent39in which a notch39ais formed so that the vent may be broken according to a suitable internal pressure, e.g., a predetermined internal pressure.

In one embodiment of the present invention, the cap plate31is formed of, for example, a thin metal plate, and includes an electrolyte injection opening27for injecting an electrolytic solution at one side, and a sealing stopper38that seals the electrolyte injection opening27secured (e.g., fixed) to the cap plate31.

The positive electrode terminal21and the negative electrode terminal22each may be disposed (e.g., installed) with a portion thereof penetrating through the cap plate31, with a first gasket25at an upper portion thereof, and with a second gasket28at a lower portion thereof. A corresponding one of the first gasket25and a corresponding one of the second gasket28are further located between the cap plate31and a corresponding one of the positive electrode terminal21or the negative electrode terminal22to insulate the cap plate from the positive electrode terminal21and/or the negative electrode terminal22.

In one embodiment of the present invention, the terminals21and22have a substantially cylindrical shape (e.g. a circular cylinder shape), on which fasteners (e.g., nuts29) that support the terminals21and22at an upper portion thereof are located (e.g., installed) on the terminals21and22. Threading, similar to that of a screw, may be formed on an outer circumference of the terminals21and22, with which a corresponding one of the nuts29may be coupled. A current collecting tap41that is electrically coupled to the positive electrode11may be at (e.g., installed on) the positive electrode terminal21, and a current collecting tap42that is electrically coupled to the negative electrode12may be at (e.g., installed on) the negative electrode terminal22.

Additionally, at a lower portion of the terminals21and22, terminal flanges21aand22athat support the terminals at the lower portion may be formed. If nuts29are fastened onto the terminals21and22, spaces between the cap plate31and the terminals21and22, respectively, are sealed by compressing the first gaskets25and the second gaskets28with the terminal flanges21aand22aand the nuts29.

In one embodiment of the present invention, a first cover60for insulation is located (e.g., installed) between the terminal flange21aand the cap plate31, and another first cover60for insulation is located (e.g., installed) between the terminal flange22aand the cap plate31. The first cover60that is at the positive electrode terminal21may couple (e.g., combine) with a second cover80by being inserted thereinto, and the first cover60that is at the negative electrode terminal22may couple (e.g., combine) with the second cover70by being inserted thereinto.

FIG. 3is an exploded perspective view in which a negative electrode terminal and a current collecting tap according to the first exemplary embodiment of the present invention are observed from above.FIG. 4is an exploded perspective view in which a terminal module according to the first exemplary embodiment of the present invention is observed from below.

With reference toFIGS. 3 and 4, since the positive electrode terminal21and the negative electrode terminal22have the same (or substantially the same) structure, a detailed description with respect to the positive electrode terminal21is given by way of reference to the negative terminal22and is omitted herein.

The negative electrode terminal22may include the terminal flange22aand a terminal pillar22cprotruding toward the upper portion of the case26on the terminal flange22a. The terminal flange22asupports the terminal pillar22cunder the cap plate31by protruding in a lateral direction of the terminal pillar22c. On the terminal flange22a, a terminal protrusion (e.g., a protrusion spot)22bprotruding along a periphery (e.g., a circumference) of a lower end of the terminal pillar22cis formed.

In one embodiment of the present invention, the current collecting tap42that is electrically coupled to the negative electrode uncoated region12ais coupled (e.g., fixed) to the negative electrode terminal22, for example, by welding. The current collecting tap42may include an upper connection portion42acoupled (e.g., welded) to the terminal flange22a, and a lower connection portion42dthat is bent at the upper connection portion41aso that it continues downwardly, and is coupled (e.g., fixed) to the negative uncoated region12a. A fixing hole42b(e.g., a welding hole) configured to receive a support protrusion22dformed on the lower portion of the terminal flange22ais located at the upper connection portion42a. In a state in which the support protrusion22dis inserted into the fixing hole42b, the support protrusion22dis secured (e.g., fixed) to the upper connection portion42a, for example, by welding.

Additionally, a fuse portion42chaving a smaller cross-section than its surroundings may be formed on the upper connection portion42a. A fuse hole42emay be formed at the center of the fuse portion42c, the fuse portion42chaving a smaller cross-section than its surroundings. However, the present invention is not limited thereto, and, alternatively, a groove may be formed at the fuse portion42c. The current collecting tap41coupled to the positive electrode terminal21may have the same, or substantially the same, structure as the current collecting tap42coupled to the negative electrode terminal22, except as to whether or not the fuse portion is formed. In one embodiment of the present invention, the fuse portion42cis on the current collecting tap42coupled to the negative electrode terminal22, but the present invention is not limited thereto, and the fuse portion may be on the current collecting tap41coupled to the positive electrode terminal21.

If the fuse portion42cis on the current collecting tap42, when an overcurrent flows, the fuse portion42cmelts, which opens a current path. If the fuse portion42cis on the current collecting tap42, when a relatively large current flows because of an occurrence of a short-circuit, the fuse is operated, such that safety may be improved.

In one embodiment of the present invention, the second gasket28includes a lower insulating portion28aconfigured to receive the terminal flange22aand an upper insulating portion28cthat covers the terminal pillar22cand protrudes upwardly. The second gasket28may be formed of, for example, a synthetic resin, e.g., a synthetic resin having elasticity.

The lower insulating portion28amay be formed to cover the upper surface and lateral surface of the terminal flange22a, and the terminal flange22amay be inserted thereinto. A groove28dinto which the terminal protrusion22bmay be inserted is formed on the lower insulating portion28a, and because of the formation of the groove28d, a step portion28bprotruding along the periphery (e.g., the circumference) of the upper insulating portion28cis formed on the second gasket28.

In one embodiment of the present invention, the step portion28bpenetrates through the hole63on the first cover60, and contacts the lower surface of the cap plate31. The step portion28bmay make contact with the cap plate31by being pressed by the terminal protrusion22b. As described above, since the step portion28bof the second gasket28having elasticity is contacted (e.g., closely contacted) with the cap plate31, a space between the cap plate31and negative electrode terminal22may be sealed (or substantially sealed). Additionally, an upper insulating portion28cmay have a cylindrical shape, and may be inserted into the terminal hole on the cap plate31, and the terminal pillar22cmay be inserted thereinto.

In one embodiment of the present invention, the first cover60is installed on the upper portion of the second gasket28, in which the first cover60is disposed between the cap plate31and the second gasket28. The hole63into which the second gasket28is inserted is formed on the first cover60, and the step portion28band the upper insulating portion28care inserted into the hole63.

The first cover60may be around (e.g., surround or cover) the upper surface and lateral surface of the second gasket28. A support protrusion64inserted into a groove formed on the cap plate31may be formed on the top surface of the first cover60. Since the support protrusion64may be installed by being inserted into the groove, the first cover60may be installed at a relatively accurate position with respect to the cap plate31, and by installing the nut29on the negative electrode terminal22, it is possible to prevent rotation of the first cover60.

The first cover60may couple with the second cover70by being inserted thereinto, and the second cover70may be installed so that the second cover and the upper connection portion42aof the current collecting tap42covers the first cover60. A cover plate61that may have, for example, a rectangular shape and a side wall62that protrudes downwardly at a side end of the cover plate61may be formed on the first cover60.

The second cover70may include a cover plate71that has, for example, a rectangular shape, and a side wall72that protrudes upwardly at a side end of the cover plate71. In one embodiment of the present invention, the side wall72protrudes at three side ends of the cover plate71and opens in a direction such that the lower connection portion42dformed on the current collecting tap42may continue downwardly. Protection protrusions75that protrude to an outside of the current collecting tap42may be formed at both side ends of the second cover70, and the lower connection portion42dmay be disposed between the protection protrusions75. If the protection protrusions75are formed, the protection protrusions75may assist the current collecting tap42to be relatively stably coupled with the negative electrode terminal22by preventing collision of the case26and the current collecting tap42when an impact is transmitted from the outside, such that short-circuiting between the case26and the current collecting tap42may be prevented.

A fuse protrusion73that is configured to protrude into a fuse hole42emay be formed on the cover plate71of the second cover70. If the fuse protrusion73is formed, the fuse protrusion73acts as a support for separating the upper connection portion42afrom the lower connection portion42dafter the fuse portion42chas melted. Without support for separation, if vibration or impact is transferred from the outside after the fuse portion42chas melted, the upper connection portion42amay be coupled again to the lower connection portion42d, and an overcurrent might flow, which may cause the rechargeable battery101to ignite or explode. However, if the fuse protrusion73is inserted into the fuse hole42e, the melted portion may be prevented from being coupled again.

A corner of the cover plate71that faces an inside of the case26on the second cover70and the side wall72may be rounded. When the external impact is transferred to the rechargeable battery101, if the electrode assembly10is raised and collides with the second cover70, the electrode assembly10may be torn, such that a short-circuit may occur. However, if a round portion is formed on the second cover70, it is possible to prevent the electrode assembly10from being damaged due to a collision of the electrode assembly10and the second cover70.

The first cover60and the second cover70may be formed of, for example, a polymer having electric insulating property, e.g., a polymer having elasticity, so that the first cover and the second cover will not, or substantially will not, react with the electrolytic solution.

The side wall62of the first cover60may be inserted into the inside of the side wall72of the second cover70, such insertion couples together the second cover70and the first cover60. However, the present invention is not limited thereto, and the sidewall72of the second cover70may be inserted into the inside of the side wall62of the first cover60.

As shown inFIGS. 2 and 5, the second gasket28, the terminal flange22a, and the upper connection portion42aof the current collecting tap42are between the second cover70and the first cover60, such that, in a state in which the first cover60and the second cover70are assembled together, the first cover and the second cover form a modular element including the negative electrode terminal22and the current collecting tap42.

When the negative electrode terminal22and the current collecting tap42are pre-assembled into a module, an assembly process of the rechargeable battery101may be relatively simplified by securing (e.g., fixing) the previously assembled negative electrode terminal22and current collecting tap42to the cap plate31. Therefore, since the negative electrode terminal, the second gasket, and the current collecting tap may not be required to be separately installed on the cap plate, an installation process may be simplified and/or shortened. Further, since the second cover70surrounds the negative electrode terminal22, the second gasket28, and the current collecting tap42, it is possible to prevent, or substantially prevent, a short-circuit from occurring due to, for example, the electrolytic solution infiltrating into the gap.

FIG. 6is a cross-sectional view that illustrates a portion of a rechargeable battery according to a second exemplary embodiment of the present invention.

Referring toFIG. 6, since a rechargeable battery102according to the second exemplary embodiment may include the same (or substantially the same) structure as the rechargeable battery101, according to the first exemplary embodiment, except for the structure of a first cover160and a second cover170, descriptions of certain aspects of the rechargeable battery102are given by way of reference to the rechargeable battery101and will be omitted herein.

The first cover160and the second cover170may be coupled together by inserting the second cover170into the first cover160. A sealant (e.g., a sealing material) (not shown) may be installed in a gap between the first cover160and the second cover170in order to prevent (or substantially prevent) intrusion of foreign materials.

A positive electrode terminal121may include a terminal flange121aand a terminal pillar121cprotruding toward the upper portion of the case on the terminal flange121a. The terminal flange121asupports the terminal pillar121cunder a cap plate131by protruding in a side direction of the terminal pillar121c. On the terminal flange121a, a terminal protrusion (e.g., a protrusion spot)121bprotruding along a periphery (e.g., a circumference) of a lower end of the terminal pillar121cmay be formed.

In one embodiment of the present invention, a second gasket128into which the terminal flange121ais inserted is installed on the upper portion of the terminal flange121a, and a current collecting tap141that is electrically coupled to the positive electrode is installed on the lower portion of the terminal flange121a. The current collecting tap141may include an upper connection portion141athat is coupled, e.g., welded, to the terminal flange121aand a lower connection portion141bthat continues downwardly at the upper connection portion141aand is coupled, e.g., fixed, to the positive electrode uncoated region111a.

The second gasket128, the terminal flange121a, and the upper connection portion141aof the current collecting tap141may be installed by being inserted between the first cover160and the second cover170, and the positive electrode terminal121and the current collecting tap141may be integrally secured, e.g., fixed.

Protection protrusions171that further protrude to an outside of the current collecting tap141may be formed at an edge in a width direction of the second cover170, and the lower connection portion141bmay be disposed between the protection protrusions171. A support spot161that supports the protection protrusion171at a lower portion thereof may be formed on the first cover160. When the support spot161is formed, the first cover160and the second cover170may be stably coupled.

Similar to what was previously described in connection with rechargeable battery101, the positive electrode terminal121and current collecting tap141may assembled into a module including the first cover160and the second cover170, thereby aiding assembly.

While aspects of the present invention have been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, instead, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.