Rechargeable battery

A rechargeable battery includes an electrode assembly including a positive electrode and a negative electrode, each of the positive and negative electrodes including a coated region and an uncoated region at an end of the coated region in a longitudinal direction of the electrode assembly, a case housing the electrode assembly, a terminal coupled to the electrode assembly, and a current collecting member electrically coupling the electrode assembly to the terminal, wherein the uncoated region is fixed to the current collecting member, and includes a portion that is substantially perpendicular to the longitudinal direction of the electrode assembly.

BACKGROUND

Embodiments of the present invention relate to a rechargeable battery.

(b) Description of the Related Art

A rechargeable battery can be repeatedly charged and discharged, unlike a primary battery, which is not designed to be recharged. A rechargeable battery having low capacity may be used for small portable electronic devices, such as mobile phones, laptop computers, and camcorders. Large capacity batteries are widely used as a power source for driving things such as motors of hybrid vehicles, etc.

Nowadays, a high power rechargeable battery using a non-aqueous electrolyte of high energy density has been developed, and the high power rechargeable battery is formed to have a large capacity by coupling a plurality of rechargeable batteries in series to drive a motor of a device, for example, an electric vehicle requiring large amounts of electric power.

Further, a battery module may have a plurality of rechargeable batteries that are coupled in series, the rechargeable batteries being, for example, cylindrically shaped or rectangularly shaped.

It is useful that such a battery module has a large capacity in a limited volume, as a volume of the battery module may impact performance of a device in which the battery module is mounted.

Further, when the battery module is mounted in an electric vehicle, vibration and impact are transferred to the battery module, and thus the battery module should have a structure capable of withstanding vibration and impact.

SUMMARY

Embodiments of the present invention provide a rechargeable battery having improved safety features.

An exemplary embodiment of the present invention provides a rechargeable battery including an electrode assembly including a positive electrode and a negative electrode, each of the positive and negative electrodes including a coated region and an uncoated region at an end of the coated region in a longitudinal direction of the electrode assembly, a case housing the electrode assembly, a terminal coupled to the electrode assembly, and a current collecting member electrically coupling the electrode assembly to the terminal, wherein the uncoated region is fixed to the current collecting member, and includes a portion that is substantially perpendicular to the longitudinal direction of the electrode assembly.

Another exemplary embodiment of the present invention provides a rechargeable battery including a plurality of electrode assemblies each including a positive electrode and a negative electrode, each of the positive and negative electrodes including a coated region and an uncoated region at an end of the coated region in a longitudinal direction of the electrode assembly, a case housing the electrode assembly, a terminal coupled to the electrode assembly, and a current collecting member electrically coupling the electrode assembly to the terminal, wherein the current collecting member includes a side plate extending in a direction substantially perpendicular to the longitudinal direction of the electrode assemblies, and a support plate coupled to the side plate and substantially parallel to the side plate, and wherein the uncoated region is bent with respect to the longitudinal direction of the electrode assembly, and coupled to the support plate.

The uncoated region may be welded to the support plate.

The uncoated region may include an inclined surface at an end of one of the electrodes of one of the electrode assemblies, a first extension extending from a peak of the inclined surface in the longitudinal direction of the electrode assembly, and a second extension extending from the first extension in a direction substantially perpendicular to the longitudinal direction of the electrode assembly.

The support plate may be bent from the side plate, and the support plate and the side plate may be integrally formed.

The support plate and the side plate may form a tube having a substantially rectangular cross-section.

The current collecting member may further include a terminal connection portion having a hole for accommodating the terminal.

The terminal connection portion may extend from the side plate in a direction substantially perpendicular to the side plate, substantially perpendicular to the support plate, and substantially parallel to the longitudinal direction of the electrode assembly.

The terminal connection portion, the side plate, and the support plate may be integrally formed.

The side plate may have an opening.

The opening of the side plate may be substantially rectangular and may extend in a longitudinal direction of the side plate.

The support plate may include a first portion coupled to a first side of the side plate, and a second portion coupled to a second side of the side plate opposite the first side, wherein the first portion is bent from the side plate to be substantially parallel to the side plate, and wherein the second portion is bent from the side plate to be substantially parallel to the side plate and to substantially overlap the first portion.

The side plate may include a first prong and a second prong, wherein the support plate includes a first support plate coupled to and bent from the first prong to form a tube-like structure with the first prong, and a second support plate coupled to and bent from the second prong to form a tube-like structure with the second prong.

According to an embodiment of the present invention, output power per volume can be increased by reducing or minimizing the space occupied by uncoated regions and current collecting members.

DETAILED DESCRIPTION

Embodiments of the present invention will be described more fully hereinafter 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 ways, all without departing from the spirit or scope of the present invention. Also, like reference numerals designate like elements throughout the specification and the drawings.

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

Referring toFIGS. 1 and 2, a rechargeable battery101according to the first exemplary embodiment includes an electrode assembly10formed by spiral-winding a positive electrode11and a negative electrode12with a separator13therebetween, a case30that houses the electrode assembly10, and a cap assembly20coupled to the case30at an opening of the case30.

The rechargeable battery101according to the first exemplary embodiment illustrates a rectangularly shaped lithium ion rechargeable battery. However, the present invention is not limited thereto, and embodiments of the present invention may include a battery of various forms such as, for example, a lithium polymer battery or a cylindrical battery.

The positive electrode11and the negative electrode12include coating regions in which an active material is applied to a current collector formed with thin plate metal foil, and uncoated regions11aand12ain which an active material is not applied.

The positive uncoated region11ais formed at a side end of the positive electrode11in a length direction of the positive electrode11, and the negative uncoated region12ais formed at a side end of the negative electrode12in a length direction of the negative electrode12and opposite the side end of the positive electrode. The positive electrode11and the negative electrode12are spiral-wound about a winding axis L1with the separator13, which is an insulator interposed therebetween. The electrode assembly10is spiral-wound and is flatly pressed to have a wide front surface. The front surface is parallel to the winding axis L1. However, the present invention is not limited thereto, and the electrode assembly10may be formed in a structure in which a positive electrode and a negative electrode formed with a plurality of sheets are stacked with a separator therebetween.

The case30is formed in an approximately cuboid shape, and has an opening at one surface thereof, while a plurality of electrode assemblies10are inserted into the case30.

The cap assembly20includes a cap plate25that covers an opening of the case30, a positive terminal21protruding outside of the cap plate25and electrically coupled to the positive electrode11, a negative terminal22protruding outside of the cap plate25and electrically coupled to the negative electrode12, and a vent member27that has a notch27aconfigured to tear or break due to internal pressure (e.g., according to a predetermined internal pressure).

The cap plate25is formed in a thin metal plate, has an electrolyte injection opening for injecting an electrolyte solution at one side thereof, and a seal stopper23for sealing the electrolyte injection opening.

The positive terminal21penetrates the cap plate25. A first gasket24positioned at an upper part between the cap plate25and the positive terminal21, and a second gasket26positioned at a lower part between the cap plate25and the positive terminal21, insulate the cap plate25and the positive terminal21.

The positive terminal21is formed in a circular cylindrical shape, a nut29that supports the positive terminal21at an upper part is installed in the positive terminal21, and a screw thread for fastening the nut29is formed at an external circumference of the positive terminal21.

The positive terminal21is electrically coupled to the positive uncoated region11ausing a positive current collecting member51as an intermediary, and a terminal flange that supports the positive terminal21and the positive current collecting member51is formed at a lower end of the positive terminal21.

The negative terminal22is installed to penetrate the cap plate25. The first gasket24positioned at an upper part between the cap plate25and the negative terminal22, and the second gasket26positioned at a lower part between the cap plate25and the negative terminal22, insulate the cap plate25and the negative terminal22.

The negative terminal22is formed in a circular cylindrical shape, the nut29that supports the negative terminal22at an upper part is installed in the negative terminal22, and a screw thread for fastening the nut29is formed at an external circumference of the negative terminal22.

The negative terminal22is electrically coupled to the negative uncoated region12ausing a negative current collecting member52as an intermediary, and a terminal flange that supports the negative terminal22and the negative current collecting member52is formed at a lower end of the negative terminal22.

FIG. 3is a perspective view illustrating a coupling state of a positive electrode current collecting member and an electrode assembly according to the first exemplary embodiment of the present invention, andFIG. 4is a transverse cross-sectional view illustrating a portion of a rechargeable battery according to the first exemplary embodiment of the present invention.

Referring toFIGS. 3 and 4, the positive electrode current collecting member51includes a terminal connection portion511fixed to the positive terminal21, a side plate513bent from the terminal connection portion511, a connection plate514bent from the side plate513, and a support plate515bent from the connection plate514.

The terminal connection portion511is formed in a quadrangular plate shape, and a hole511a, through which a protrusion formed in a lower portion of the positive terminal21is inserted, is in the center of the terminal connection portion511. Further, the terminal connection portion511is bonded to a lower portion of the positive terminal21by, for example, welding.

The side plate513is bent orthogonally toward the bottom of the case30at an end portion of a length direction of the terminal connection portion511. The side plate513is coupled in a height direction of the case30, and is parallel to a side surface of the case30. A hole is formed in the side plate513(e.g., in a height direction). Further, the side plate513is between the electrode assemblies10and is vertical and in a direction perpendicular to the winding axis L1of the electrode assembly10(the winding axis being the x-axis direction ofFIG. 4) to be parallel to a stacking direction (y-axis direction ofFIG. 4) of the electrode assembly10. However, the present invention is not limited thereto, and the side plate513may cross the winding axis L1.

The connection plate514is coupled to both side ends of the side plate513, and is bent vertically toward a side surface of the case30from the side plate513. Accordingly, the connection plate514is parallel to the winding axis L1. The support plate515is bent from the connection plate514to cross a direction of a wide front surface of the electrode assembly10, and end portions of the support plate515bent from both sides of the connection plate514come in contact and are supported by each other. Accordingly, the support plate515is in a direction that crosses the winding axis L1.

In the present exemplary embodiment, the support plate515is bent from the side plate513with the connection plate514acting as an intermediary, but the present invention is not limited thereto, and the support plate515may be directly coupled to the side plate513and bent therefrom. Further, the support plate515is bent vertically from the connection plate514to be parallel to the side plate513, but the present invention is not limited thereto.

The positive uncoated region11ais fixed to the connection plate514and the support plate515(e.g., by welding). The positive uncoated region11aincludes an inclined surface11aathat is formed obliquely toward the center of a width direction of the electrode assembly10, a first extension11acthat is parallel to the winding axis L1, that couples the inclined surface11aaand a second extension11ab, and that is attached to the connection plate514, and the second extension11ab, which is attached to the support plate515and bent from the first extension11acand the inclined surface11aato cross the winding axis L1. The second extension11abis bent vertically to the winding axis L1, crosses a direction of a wide front surface of the electrode assembly, and is parallel to a side surface of the case30.

Further, the second extension11abof the adjacent electrode assembly10is bent toward the positive uncoated region11aof the neighboring electrode assembly10, and end portions of the second extensions11abare coupled together.

As described above, according to the present exemplary embodiment, a portion that is coupled to the positive uncoated region11ain the positive electrode current collecting member51is formed in a pipe shape having a substantially rectangular cross-section formed by the side plate513, the connection plate514, and the support plate515. Further, the positive uncoated region11ais installed to enclose the connection plate514and the support plate515.

In the present exemplary embodiment, when the bent support plate515is provided, a contact area of the positive electrode current collecting member51and the positive uncoated region11ais enlarged, thereby stably fixing the electrode assembly10. Further, by reducing size of the positive electrode current collecting member51, output per volume can be improved. A conventional uncoated region protrudes in a direction of a winding axis, and a current collecting member is parallel to the uncoated region, and according to such a structure, space corresponding to a protruded length of the uncoated region would occupy volume, potentially leading to an increase in volume of the battery. However, according to the present exemplary embodiment, by reducing occupying space of the positive uncoated region11aand the positive electrode current collecting member51, output per volume is remarkably improved.

Further, as shown inFIG. 4, the positive uncoated region11ahas a second extension11abthat is bent toward the inclined surface11aaand a first extension11acprotruding in a direction of the winding axis L1and that couples the inclined surface11aaand the second extension11ab. Because the second extension11aband the first extension11acare fixed to the positive electrode current collecting member51, the positive uncoated region11ais supported by the positive electrode current collecting member51in two directions to prevent poor contact of the positive uncoated region11aand the positive electrode current collecting member51due to vibration or impact.

FIG. 5is a perspective view illustrating a negative electrode current collecting member according to the first exemplary embodiment of the present invention.

Referring toFIG. 5, the negative electrode current collecting member52includes a terminal connection portion521that is fixed to the negative terminal22, a side plate523that is bent from the terminal connection portion521, a connection plate524that is bent from the side plate523, and a support plate525that is bent from the connection plate524.

The terminal connection portion521is of a quadrangular plate shape, and a hole521a, which is for inserting a protrusion of a lower portion of the positive terminal21, is formed at the center thereof. Further, the terminal connection portion521is bonded (e.g., bonded by welding) to a lower portion of the positive terminal21. The side plate523is formed in a height direction of the case30, and a hole526is formed in the side plate523(e.g., at a height direction).

The negative electrode current collecting member52according to the present embodiment is formed in the same structure as that of the positive electrode current collecting member51, and thus a detailed description of structure the same as that of the positive electrode current collecting member52will be omitted.

FIG. 6Ais a cross-sectional view illustrating a state in which a current collecting member is coupled to an uncoated region, andFIG. 6Bis a cross-sectional view illustrating a state in which a current collecting member is bent.

A method of installing a current collecting member according to the present embodiment will be described with reference toFIGS. 6A and 6B. The method of installing current collecting members51and52according to the present exemplary embodiment includes respectively inserting the current collecting members51and52between the uncoated regions11aand12aof the neighboring electrode assembly10, respectively bonding the uncoated regions11aand12ato protrusions bent at both side ends of the side plates513and523, and adjusting protruding angles of the protrusions.

At a step of inserting, the side plates513and523are respectively inserted between the uncoated regions11aand12a, and protrusions at both side ends of the side plates513and523closely contact respective ones of the uncoated regions11aand12a. In this case, the protrusions are parallel to the uncoated regions11aand12aand the winding axis L1.

At a step of bonding, the uncoated regions11aand12aand the respective protrusions are bonded (e.g., bonded with ultrasonic welding and/or resistance welding). Next, at a step of adjusting a protruding angle, by bending an opposite protrusion toward a neighboring protrusion, the connection plates514and524and the support plates515and525are formed.

FIG. 7is a transverse cross-sectional view illustrating a rechargeable battery according to a second exemplary embodiment of the present invention, andFIG. 8is a perspective view illustrating a current collecting member according to the second exemplary embodiment of the present invention.

Referring toFIGS. 7 and 8, a rechargeable battery102according to the present exemplary embodiment includes a case31, a plurality of electrode assemblies10installed within the case31, and current collecting members53and54that couple the electrode assembly10and a terminal.

The rechargeable battery102according to the present embodiment is formed identically or similarly to the rechargeable battery according to the first exemplary embodiment, except for the number of the electrode assemblies10and a structure of the current collecting members53and54. Accordingly, description of structure identical or similar to that of the first exemplary embodiment will be omitted.

Four electrode assemblies10are installed within the case31, a positive electrode current collecting member53is coupled to a positive uncoated region11a, and a negative electrode current collecting member54is coupled to a negative uncoated region12a.

The positive electrode current collecting member53includes a terminal connection portion531fixed to a positive terminal21, an upper side plate532bent from the terminal connection portion531, two lower side plates533coupled at a lower portion of the upper side plate532and separated from each other to be coupled to a lower part, a connection plate534bent from the lower side plate533, and a support plate535bent from the connection plate534.

The negative electrode current collecting member54is formed in the same structure as that of the positive electrode current collecting member53, and thus a description of the positive electrode current collecting member53replaces a description of the negative electrode current collecting member54.

The terminal connection portion531is formed in a quadrangular plate shape, and a hole, through which the positive terminal21is inserted, is formed in the center of the terminal connection portion531. Further, the terminal connection portion531is bonded by welding to a lower portion of the positive terminal21.

The upper side plate532is bent orthogonally toward the bottom of the case30in an end portion of a length direction of the terminal connection portion531. The upper side plate532is formed in a height direction of the case30, and lower side plates533, which are coupled to the upper side plate532, are formed at a lower end of the upper side plate532. Two lower side plates533are formed downward from both side ends of the upper side plate532. The connection plate534is coupled to both side ends of the lower side plate533, is bent vertically from the lower side plate533, and is parallel to the winding axis L1. The support plate535that is vertically bent from the connection plate534is formed at the side end of the connection plate534.

The positive uncoated region11aand the negative uncoated region12aare fixed (e.g., fixed by welding) to the connection plate534and the support plate535.

FIG. 9is a transverse cross-sectional view of a rechargeable battery according to a third exemplary embodiment of the present invention, andFIG. 10is a perspective view illustrating a current collecting member according to a third exemplary embodiment of the present invention.

Referring toFIGS. 9 and 10, a rechargeable battery103according to the present embodiment includes a case30, a plurality of electrode assemblies110installed within the case30, and current collecting members55and56that couple the electrode assemblies110and a terminal.

The rechargeable battery103according to the present embodiment is formed identically or similarly to the rechargeable battery according to the first exemplary embodiment, except for a structure of the electrode assembly110and the current collecting members55and56. Accordingly, detailed description of structure identical or similar to that of the first exemplary embodiment will be omitted.

The rechargeable battery103according to the present embodiment includes a case30, a plurality of electrode assemblies110installed within the case30, and current collecting members55and56that couple the electrode assemblies110and a terminal.

Two electrode assemblies110are installed within the case30, the positive electrode current collecting member55is coupled to the positive uncoated regions111a, and the negative electrode current collecting member56is coupled to the negative uncoated regions112a.

The negative electrode current collecting member56includes a terminal connection portion561that is fixed to a negative terminal, a side plate563bent from the terminal connection portion561to be coupled to a lower part, and a support plate564parallel to the side plate563.

The terminal connection portion561is formed in a quadrangular plate shape, and a hole561a, through which a protrusion corresponding to a lower end of the negative terminal is inserted, is formed at the center thereof. Further, the terminal connection portion561is bonded (e.g., welded) to a lower part of the negative terminal.

The side plate563is bent orthogonally toward the bottom of the case30at an end portion of a length direction of the terminal connection portion561. The side plate563is formed in a height direction of the case30, and a hole566is formed in the side plate563. The side plate563is parallel to a stacking direction of the electrode assembly110and is vertical to the winding axis L1.

The support plate564is coupled to both side ends of the side plate563, and protrudes parallel to the side plate563at side ends of the side plate563. Accordingly, the side plate563and the support plate564are in the same plane.

The positive electrode current collecting member55is formed in the same or similar structure as that of the negative electrode current collecting member56, and thus a detailed description of the structure that is the same as or similar to that of the negative electrode current collecting member56will be omitted.

As shown inFIGS. 9 and 11A, the positive uncoated region111ais fixed by welding to the support plate554. The positive uncoated region111aincludes an inclined surface111aaformed obliquely toward the center of a width direction of the electrode assembly10, and a second extension111abattached to the support plate564and bent to the inclined surface111aato cross the winding axis. The second extension111abis bent vertically toward the winding axis L1, and is parallel to a side surface of the case30. The second extensions111abof the adjacent electrode assembly10are bent toward the outside of the case30.

The negative uncoated region112ais fixed (e.g., welded) to the support plate564, and includes an inclined surface112aaformed obliquely toward the center of a width direction of the electrode assembly10, and a second extension112abattached to the support plate564and bent toward the inclined surface112aato cross the winding axis L1. The second extension112abis bent vertically to the winding axis L1and is parallel to a side surface of the case30. The second extensions112abof the adjacent electrode assembly10are bent toward the outside of the case30.

In the present exemplary embodiment, in the uncoated regions111aand112a, when the second extensions111aband112ab, which are respectively bent to the inclined surfaces111aaand112aa, are formed, and when the support plates554and564, which are respectively coupled to the side end of the side plates553and563, are formed, occupying space of the uncoated regions111aand112aand the current collecting members55and56is reduced or minimized, and output per volume can be significantly improved.

FIG. 11Ais a cross-sectional view illustrating a state in which a current collecting member is coupled to an uncoated region, andFIG. 11Bis a cross-sectional view illustrating a state in which a current collecting member is unbent.

A method of installing a current collecting member according to the present exemplary embodiment will be described with reference toFIGS. 11A and 11B. The method of installing the current collecting members55and56according to the present exemplary embodiment includes respectively inserting the current collecting members55and56between the uncoated regions111aand112aof the neighboring electrode assembly110, bonding the uncoated regions111aand112ato a bent protrusion at both side ends of respective ones of the side plates553and563, and adjusting a protruding angle of an opposite protrusion.

At a step of inserting, the side plates553and563are inserted between respective ones of the uncoated regions111aand112a, and protrusions that respectively protrude from both side ends of the side plates553and563closely contact the uncoated regions111aand112a. In this case, the protrusion is parallel to the uncoated regions111aand112aand the winding axis L1.

At a step of bonding, the uncoated regions111aand112aand the respective protrusions are bonded (e.g., bonded by ultrasonic welding and/or resistance welding). Next, at a step of adjusting a protruding angle, the side plates553and563are formed by spreading (e.g., spreading flat, or unbending) a protrusion that is opposite to be parallel to the support plates554and564.

FIG. 12is a transverse cross-sectional view of a rechargeable battery according to a fourth exemplary embodiment of the present invention, andFIG. 13is a perspective view illustrating a current collecting member according to the fourth exemplary embodiment of the present invention.

Referring toFIGS. 12 and 13, a rechargeable battery104according to the present embodiment includes a case30, a plurality of electrode assemblies120installed within the case30, and current collecting members57and58that couple the electrode assemblies120and a terminal.

The rechargeable battery104according to the present embodiment is formed identically or similarly to the rechargeable battery according to the first exemplary embodiment, except for a structure of the electrode assembly120and the current collecting members57and58. Accordingly, a description of structure that is identical or similar to that of the first exemplary embodiment will be omitted.

The rechargeable battery104according to the present embodiment includes a case30, a plurality of electrode assemblies120within the case30, and current collecting members57and58that couple the electrode assembly120and a terminal.

In the present embodiment, two electrode assemblies120are installed within the case30, the positive electrode current collecting member57is coupled to positive uncoated regions121a, and the negative electrode current collecting member58is coupled to negative uncoated regions122a.

The positive electrode current collecting member57includes a terminal connection portion571that is fixed to a positive terminal, a side plate573that is bent from the terminal connection portion571to be coupled to a lower part, a first support plate574that is bent from one side end of the side plate573to be parallel to the side plate573, and a second support plate576that is bent from the other side end of the side plate573to be parallel to the side plate573.

The terminal connection portion571is formed in a quadrangular plate shape, and a hole571a, which is for receiving a protrusion corresponding to a lower end of the positive terminal, is formed at the center of the terminal connection portion571. Further, the terminal connection portion571is bonded (e.g., welded) to a lower part of the positive terminal.

The side plate573is bent orthogonally toward the bottom of the case30in an end portion of a length direction of the terminal connection portion571. The side plate573is formed in a height direction of the case30, and a hole is formed in the side plate573.

The first support plate574is coupled to one side end of the side plate573, and the second support plate576is coupled to the other side end of the side plate573. The second support plate576is at the outside of the first support plate574, and thus the first support plate574is between the side plate573and the second support plate576.

The side plate573, the first support plate574, and the second support plate576cross the winding axis L1(e.g., are perpendicular to the winding axis L1).

One positive uncoated region121aof an electrode assembly120is fixed (e.g., welded) to the first support plate574, and the other positive uncoated region121aof the other electrode assembly120is fixed (e.g., welded) to the second support plate576.

The positive uncoated region121aincludes an inclined surface121aaformed obliquely toward the center of a width direction of the electrode assembly10, a second extension121abcoupled to the support plate574and bent toward the inclined surface121aato cross the winding axis L1, and a first extension121acthat couples the second extension121aband the inclined surface121aa.

The second extension121abis bent to be orthogonal to the winding axis L1and to be parallel to a side surface of the case30, and the second extension121abof one electrode assembly120(e.g., the top electrode assembly120inFIG. 12) is at the outside further than (e.g., is closer to the case30than) the other second extension121abof the neighboring electrode assembly120(e.g., the bottom electrode assembly120inFIG. 12). Further, the second extension121abof the neighboring electrode assembly is between the support plates574and576.

The negative electrode current collecting member58is formed in the same structure as that of the positive electrode current collecting member57and thus a detailed description of the structure that is the same as that of the positive electrode current collecting member57will be omitted.

The negative uncoated region122aincludes an inclined surface122aaformed obliquely toward a center of a width direction of the electrode assembly10, a second extension122abattached to the support plate584or586and bent from the inclined surface122aato cross the winding axis L1, and a first extension122acthat couples the second extension122aband the inclined surface122aa.

The second extension122abis bent vertically to the winding axis L1to be parallel to a side surface of the case30, and the second extension122abof one side of the adjacent electrode assembly10is at the outside further than the other second extension122abof the neighboring electrode assembly10. Further, the second extension122abof one side electrode assembly is inserted between support plates.

As described above, according to the present exemplary embodiment, when an uncoated region is fixed to the support plate, because the support plates are bent and stacked, the uncoated region is located between the support plates to be stably fixed, and by reducing a volume of the uncoated region and the current collecting member, output per volume can be improved.

FIG. 14Ais a cross-sectional view illustrating a state in which a current collecting member is coupled to an uncoated region,FIG. 14Bis a cross-sectional view illustrating a state in which a first support plate is bent, andFIG. 14Cis a cross-sectional view illustrating a state in which a second support plate is also bent.

A method of installing a current collecting member according to the present embodiment will be described with reference toFIGS. 14A and 14C. The method of installing current collecting members57and58according to the present exemplary embodiment includes inserting the current collecting members57and58between respective ones of the uncoated regions121aand122aof the neighboring electrode assemblies120, bonding the uncoated regions121aand122ato the bent protrusions at both side ends of the side plates573and583, and adjusting protruding angles of opposite protrusions.

At a step of inserting, the side plates573and583are respectively inserted between the uncoated regions121aand122a, and protrusions at both side ends of the side plates573and583closely contacts the uncoated regions121aand122a, respectively. In this case, the protrusions are parallel to the uncoated regions121aand122aand the winding axis L1.

At a step of bonding, the uncoated regions121aand122aand the protrusions are respectively bonded (e.g., bonded by ultrasonic welding and/or resistance welding). Next, a step of adjusting a protruding angle of a protrusion includes a step of bending the first support plates574and584and the corresponding protrusion toward respective ones of the side plates573and583, and a step of bending the second support plates576and586to form a stacked structure with the first support plates574and584.

The first support plates574and584are bent toward the neighboring second support plates576and586, and the second support plates576and586are bent to be stacked with the first support plates574and584. Accordingly, the side plates573and583, the first support plates574and584, and the second support plates576and586are stacked.