Secondary battery

A secondary battery comprises: a plurality of cylindrical electrode assemblies, wherein each electrode assembly comprises a positive electrode plate and a negative electrode plate rolled together with a separator interposed between the positive electrode plate and the negative electrode plate; a can housing the plurality of electrode assemblies; a cap assembly sealing the can; a positive electrode tab coupled to the positive electrode plate in each electrode assembly; and a negative electrode tab coupled to the negative electrode plate in each electrode assembly, wherein a first plurality of positive electrode tabs is aligned along a first line when viewed in one direction, and wherein a first plurality of negative electrode tabs is aligned along a second line when viewed in the one direction.

BACKGROUND

Aspects of the present invention relate to a secondary battery.

Secondary batteries include an electrode assembly formed by sequentially stacking a positive electrode plate, a negative electrode plate and a separator and winding the same in one direction, a can housing the cylindrical electrode assembly, and a cap plate sealing an open portion of the prismatic can to thereby form a bare cell. The secondary battery generally includes an electrode terminal insulated from the cap plate and serving one of electrodes in the secondary battery. The cap plate and the can may serve the other electrode in the secondary battery.

In the secondary battery, the electrode assembly is wound and then housed into a can in a planar state. When the electrode assembly swells during repeated charge/discharge operations, both of the planar side surfaces of the electrode assembly also swell.

Accordingly, the swelling of the electrode assembly may result in swelling of the can, specifically both side surfaces which have relatively large areas.

In order to achieve the above and other aspects of the present invention, one embodiment of the present invention provides a secondary battery including a plurality of cylindrical electrode assemblies, which is capable of preventing a prismatic can from swelling.

At least one of the above and other features and advantages may be realized by providing a secondary battery including a plurality of cylindrical electrode assemblies wound in a jelly-roll configuration, each having a positive electrode tab connected to a positive electrode plate, and a negative electrode tab connected to a negative electrode plate, a prismatic can housing the plurality of cylindrical electrode assemblies, center pins inserted into the plurality of cylindrical electrode assemblies and coupled to the bottom of the can, and a cap assembly sealing the prismatic can.

In the secondary battery according to the embodiments, swelling of the prismatic can may be prevented by forming a plurality of cylindrical electrode assemblies wound in a jelly-roll configuration and housed in the prismatic can.

SUMMARY

According to an embodiment of the invention, a secondary battery comprises a plurality of electrode assemblies, wherein each electrode assembly comprises a positive electrode plate and a negative electrode plate rolled together with a separator interposed between the positive electrode plate and the negative electrode plate. The secondary battery may comprise a can housing the plurality of electrode assemblies; a cap assembly sealing the can; a positive electrode tab coupled to the positive electrode plate in each electrode assembly; and a negative electrode tab coupled to the negative electrode plate in each electrode assembly. A first plurality of positive electrode tabs is aligned along a first line when viewed in one direction, and a first plurality of negative electrode tabs is aligned along a second line when viewed in the one direction.

According to an aspect, the secondary battery further comprises a second plurality of positive electrode tabs aligned along a third line when viewed in the one direction.

According to an aspect, the secondary battery further comprises a second plurality of negative electrode tabs aligned along a fourth line when viewed in the one direction.

According to an aspect, the secondary battery further comprises a third plurality of positive electrode tabs aligned along a fifth line when viewed in the one direction.

According to an aspect, the secondary battery further comprises a third plurality of negative electrode tabs aligned along a sixth line when viewed in the one direction.

According to an aspect, the first plurality of positive electrode tabs is connected to a positive connection tab, and wherein the first plurality of negative electrode tabs is connected to a negative connection tab.

According to an aspect, the first plurality of positive electrode tabs is connected to a first positive connection tab, the first plurality of negative electrode tabs is connected to a first negative connection tab, the second plurality of positive electrode tabs is connected to a second positive connection tab, and the second plurality of negative electrode tabs is connected to a second negative connection tab.

According to an aspect, the first plurality of positive electrode tabs is connected to a first positive connection tab, the first plurality of negative electrode tabs is connected to a first negative connection tab, the second plurality of positive electrode tabs is connected to a second positive connection tab, the second plurality of negative electrode tabs is connected to a second negative connection tab, the third plurality of positive electrode tabs is connected to a third positive connection tab, and the third plurality of negative electrode tabs is connected to a third negative connection tab.

According to an aspect, the first plurality of positive electrode tabs and the second plurality of positive electrode tabs are connected to a first positive connection tab.

According to an aspect, the first plurality of negative electrode tabs and the second plurality of negative electrode tabs are connected to a first negative connection tab.

According to an aspect, the third plurality of positive electrode tabs is connected to a second positive electrode tab, and the third plurality of negative electrode tabs is connected to a second negative connection tab.

According to an aspect, the first plurality of positive electrode tabs and the first plurality of negative electrode tabs are coupled to a first plurality of electrode assemblies.

According to an aspect, the second plurality of positive electrode tabs and the third plurality of negative electrode tabs are coupled to a second plurality of electrode assemblies.

According to an aspect, the third plurality of positive electrode tabs and the second plurality of negative electrode tabs are coupled to a third plurality of electrode assemblies.

According to an embodiment of the invention, a secondary battery comprises a plurality of electrode assemblies, a can housing the plurality of electrode assemblies, a cap assembly sealing the can, a positive electrode tab coupled to each electrode assembly, and a negative electrode tab coupled to each electrode assembly. The secondary battery may comprise a pin inserted in at least one electrode assembly, wherein the pin is coupled to the bottom surface of the can. A plurality of positive electrode tabs are aligned along a first line when viewed in one direction, and a plurality of negative electrode tabs are aligned along a second line when viewed in the one direction.

According to an aspect, a bottom surface of the pin is welded to the bottom surface of the can.

According to an aspect, the pin comprises a blade extending from a bottom portion of the pin, and the blade is welded to the bottom surface of the can.

According to an aspect, a bottom portion of the pin is bent outwards, and the bent portion is welded to the bottom surface of the can.

According to an aspect, a bottom portion of the pin is engaged with a protrusion formed on the bottom surface of the can.

According to an aspect, the pin comprises a metallic material. According to an aspect, the pin comprises a plastic material.

According to an aspect, the pin has a hollow and cylindrical shape.

According to an aspect, the pin comprises a length in a range of approximately 90% to approximately 110% a total length of the electrode assembly.

According to an aspect, the electrode assembly is cylindrical, and the pin is inserted into a center portion of the cylindrical electrode assembly.

According to an aspect, the positive electrode tabs and the negative electrode tabs have major surfaces that face each other.

According to an aspect, the cap assembly comprises an insulation case, and the positive electrode tabs and the negative electrode tabs are inserted through holes formed in the insulation case.

According to an aspect, the cap assembly further comprises a cap plate, and the negative electrode tabs are electrically connected to electrode terminals positioned on an upper surface of the cap plate.

According to an aspect, the positive electrode tabs are electrically connected to a lower surface of the cap plate.

According to an aspect, the positive electrode tabs are electrically connected to an inner surface of the can.

According to an aspect, the secondary battery further comprises a plurality of pins, wherein each pin is inserted in each of the electrode assemblies, and wherein each pin is coupled to the bottom surface of the can.

DETAILED DESCRIPTION

Embodiments will now be described more fully hereinafter with reference to the accompanying drawings.

FIG. 1Ais an exploded perspective view of a secondary battery according to an embodiment of the present invention, andFIG. 1Bis an enlarged view illustrating a portion “3” indicated by a dashed dot line inFIG. 1A.

FIG. 2is a sectional view taken along line2-2′ inFIG. 1A. For clarity of description, it is noted thatFIG. 2is obtainable when the electrode assemblies shown inFIG. 1Aare rotated by 90 degrees.

Referring toFIG. 1A, the secondary battery100according to the illustrated embodiment includes a can120, a plurality of electrode assemblies130, center pins140, and a cap assembly150.

In the secondary battery100, the plurality of cylindrical electrode assemblies130may be inserted into the prismatic can120through an upper open portion formed in the prismatic can120. The center pins140may be inserted into centers of the cylindrical electrode assemblies130, and may be fixed to the bottom of the can120. The can120may be sealed by the cap assembly150.

The can120may include an opening122. The can120may have a substantially cuboid shape, and side edges thereof may be rounded. In addition, the can120may be made of a lightweight, conductive metal such as aluminum or an aluminum alloy, but aspects of the present invention are not limited thereto. In addition, the can120can function as an electrode terminal and may be a positive electrode. Preferably, the can120may be formed by deep drawing, but aspects of the present invention are not limited thereto.

In addition, an electrolytic solution (not shown) may be injected into the can120, allowing lithium ions to move between positive and negative electrode plates, the lithium ions generated by an electrochemical reaction carried out in the battery during charge/discharge operations. The electrolytic solution (not shown) may be a non-aqueous organic electrolytic solution prepared by mixing a lithium salt and a high-purity organic solvent. In addition, the electrolytic solution (not shown) may be a polymer using a polymeric electrolyte, but is not limited thereto.

The opening122may be formed on a top portion of the can120, the electrode assemblies130may be inserted into the can120through the opening122. The opening122may be sealed by the cap assembly150.

The electrode assemblies130may include two or more unit electrode assemblies130. In an exemplary embodiment, the electrode assemblies130may include a first electrode assembly132, a second electrode assembly134, and third electrode assembly136. The first electrode assembly132, the second electrode assembly134, and the third electrode assembly136may be inserted into a single prismatic can120while being spaced apart from each other at minimum intervals.

While three of the electrode assemblies130are illustrated herein, aspects of the present invention are not limited thereto and multiple electrode assemblies may be provided.

The first electrode assembly132may include a first positive electrode tab132dand a first negative electrode tab132eelectrically connected to a first positive electrode plate132aand a first negative electrode plate132b, respectively. The second electrode assembly134may include a second positive electrode tab134dand a second negative electrode tab134eelectrically connected to a second positive electrode plate134aand a second negative electrode plate134b, respectively. In addition, the third electrode assembly136may include a third positive electrode tab136dand a third negative electrode tab136eelectrically connected to a third positive electrode plate136aand a third negative electrode plate136b, respectively. Here, the first positive electrode tab132d, the second positive electrode tab134dand the third positive electrode tab136dare electrically connected. In addition, the first negative electrode tab132e, the second negative electrode tab134eand the third negative electrode tab136eare also electrically connected. The first positive electrode tab132d, the second positive electrode tab134dand the third positive electrode tab136d, and the first negative electrode tab132e, the second negative electrode tab134eand the third negative electrode tab136eare all formed to face the opening122of the can120.

In addition, the first electrode assembly132, the second electrode assembly134and the third electrode assembly136may be electrically connected in parallel.

Since the first electrode assembly132, the second electrode assembly134and the third electrode assembly136can have substantially the same configurations, the following description will focus on the first electrode assembly132.

The first electrode assembly132includes a first positive electrode plate132a, a first negative electrode plate132b, and a first separator132c. The first electrode assembly132may be fabricated by stacking the first positive electrode plate132aand the first negative electrode plate132bwith the first separator132cinterposed therebetween, and the resulting structure may be wound into a jelly roll configuration.

The first positive electrode plate132acan include a positive electrode collector formed of a highly conductive metal foil, for example, aluminum (Al) foil, and a positive electrode active material coated on a surface of the positive electrode collector. A portion of the positive electrode collector, where the positive electrode active material is not coated, that is, a positive electrode uncoated portion, may be formed at both ends of the first positive electrode plate132a, and the first positive electrode tab132dmade of Al may be welded to one side of the positive electrode uncoated portion.

The first negative electrode plate132bcan include a negative electrode collector formed of a conductive metal foil, for example, copper (Cu) foil, and a negative electrode active material coated on a surface of the negative electrode collector. A portion of the negative electrode collector, where the negative electrode active material is not coated, that is, a negative electrode uncoated portion, may be formed at both ends of the first negative electrode plate132b, and the first negative electrode tab132emade of nickel (Ni) may be welded to one side of the negative electrode uncoated portion.

The first separator132cis positioned between the first positive electrode plate132aand the first negative electrode plate132b. The separator132cmay be formed of a porous film made of polyethylene (PE), polypropylene (PP), or a combination thereof, but aspects of the present invention are not limited thereto.

The first separator132ccan inhibit electronic conduction in the first electrode assembly132with the first positive electrode plate132aand the first negative electrode plate132band permit lithium ions to pass therebetween.

The first separator132ccan inhibit the first positive electrode plate132aand the first negative electrode plate132bfrom contacting each other, and prevent the temperature of the secondary battery100from increasing by shutting down the flow of current when the temperature of the secondary battery100rises due to an external short. In order to prevent a short between the first positive electrode plate132aand the first negative electrode plate132b, a ceramic layer prepared by mixing a ceramic material with a binder may further be provided in addition to the first separator132c.

In addition, the first separator132cis preferably wider than the first positive electrode plate132aand the first negative electrode plate132bin inhibiting a short between electrode plates.

Each of the center pins140is shaped of a hollow cylinder. In addition, the length of the center pin140is preferably approximately 90 to approximately 110% of the total length of the first electrode assembly132. If the length of the center pin140is less than or equal to 90% of the total length of the first electrode assembly132, the first electrode assembly132can be fixed or supported in a weak state. Meanwhile, if the length of the center pin140is greater than or equal to 110% of the total length of the first electrode assembly132, the center pin140may contact components of the cap assembly150, which is not desirable.

The center pins140may be made of a metal. The center pins140are inserted into a space formed in the center of the first electrode assembly132. The center pins140may be welded to the bottom of the can120. The center pins140can support the first electrode assembly132, and suppress deformation and movement of the first electrode assembly132due to charge/discharge operations. In addition, since the center pins140are formed in the first electrode assembly132, the second electrode assembly134and the third electrode assembly136, respectively, it can inhibit each electrode assembly from moving due to a volumetric change.

The cap assembly150may include a cap plate151, a gasket152, an electrode terminal153, an insulation plate154, a terminal plate155, an insulation case156, and a plug157.

The cap assembly150may be sized and shaped corresponding to the opening122of the can120, and may be installed in the opening122of the can120to be sealed.

The cap plate151may be a planar metal member sized and shaped corresponding to an entrance of the can120. The cap plate151may be coupled to the can120by, for example, welding, and can function as the same electrode as the can120, that is, a positive electrode. In order to facilitate welding, the can120and the cap plate151may be made of the same electrically conductive metal, such as aluminum or an aluminum alloy. An electrolyte injection hole151athrough which an electrolytic solution is injected may be formed at one side of the cap plate151.

The first positive electrode tab132d, the second positive electrode tab134d, and the third positive electrode tab136dare welded to the bottom surface of the cap plate151to then be electrically connected, so that the outside of the secondary battery100, excluding the electrode terminal153, can function as a positive electrode terminal. Here, the positive electrode tabs132d,134d, and136dmay penetrate throughholes156aformed in the insulation case156, respectively, which will later be described, and then be adhered to a bottom surface of the cap plate151after being bent if necessary. Alternatively, the first positive electrode tab132d, the second positive electrode tab134d, and the third positive electrode tab136dmay also be directly electrically connected to an inner surface of the can120.

According to an embodiment, the gasket152is tubular and positioned on an outer surface of the electrode terminal153. The gasket152may insulate the electrode terminal153from the cap plate151.

The electrode terminal153may be positioned at the cap assembly150, and extend through the cap plate151while surrounding the outer circumference surface of the gasket152. The first negative electrode plate132b, the second negative electrode tab134b, and the third negative electrode tab136bmay be electrically connected to the electrode terminal153, functioning as a negative electrode terminal.

According to an embodiment, the insulation plate154is plate-shaped and positioned on the bottom surface of the cap plate151. The insulation plate154may be made of the same insulating material as the gasket152. Therefore, the cap plate151and the terminal plate155to be described later may be insulated from each other by the insulation plate154.

The terminal plate155may be made of a metal and is positioned on the bottom surface of the insulation plate154. The electrode terminal153may be riveted by the terminal plate155, so that it may not be dislodged from the cap plate151.

The first negative electrode tab132e, the second negative electrode tab134e, and the third negative electrode tab136emay be directly welded to the terminal plate155, and the terminal plate155may be installed to be electrically conducted to the electrode terminal153, thereby allowing the electrode terminal153to function as a negative electrode terminal. Here, the negative electrode tabs132e,134e, and136emay penetrate the throughholes156aformed in the insulation case156, respectively, which will later be described, and then be adhered to the bottom surface of the cap plate151after being bent if necessary.

Meanwhile, the terminal plate155may not be provided, and accordingly, the first negative electrode tab132e, the second negative electrode tab134e, and the third negative electrode tab136emay be directly connected to the electrode terminal153.

According to an embodiment, the insulation case156is installed between the electrode assembly130, specifically the electrode assemblies132,134and136, and the cap assembly150to prevent the electrode assemblies132,134and136from moving up and down. In addition, the insulation case156may be installed to prevent the electrode assemblies132,134and136from being directly shorted to the cap assembly150. In addition, the insulation case156can include a plurality of throughholes156aand156bto allow the positive electrode tabs132d,134d, and136dand the negative electrode tabs132e,134e, and136eto pass therethrough upwardly. Further, the electrolytic solution injected through the electrolyte injection hole151amay be provided to the lower electrode assemblies132,134and136via the throughholes156aand156bof the insulation case156. The insulation case156may be made of a polymeric resin having an insulating property, preferably, polypropylene.

The plug157may be provided to seal the electrolyte injection hole151aafter the electrolytic solution is injected into the can120through the electrolyte injection hole151a. The plug157may be generally made of aluminum or an aluminum containing metal. The plug157may be mechanically pressed into the electrolyte injection hole151aand then engaged with the electrolyte injection hole151a.

A secondary battery200according to another embodiment of the present invention will now be described.

FIG. 3is a vertical section view illustrating a portion corresponding toFIG. 2in a secondary battery according to another embodiment of the present invention.

The secondary battery200according to the illustrated embodiment of the present invention includes a can120, electrode assemblies130, center pins240, and a cap assembly150.

Referring toFIG. 1B, which is an enlarged view illustrating a portion “3” indicated by a dashed dot line inFIG. 1A, main surfaces132f,134fand136fof the plurality of positive electrode tabs132d,134dand136dare formed to face main surfaces132h,134hand136hof the plurality of negative electrode tabs132e,134eand136e. The main surfaces132f,134fand136fof the plurality of positive electrode tabs132d,134dand136dand the main surfaces132h,134hand136hof the plurality of negative electrode tabs132e,134eand136eface a main surface120aof the can120. Narrow surfaces132g,134gand136gof the plurality of positive electrode tabs132d,134dand136dand narrow surfaces132i,134iand136iof the plurality of negative electrode tabs132e,134eand136eface a round surface120bof the can120.

The positive electrode tabs132d,134dand136dare aligned along a line, which means that the negative electrode tabs132e,134eand136eare not positioned along the line formed by the plurality of positive electrode tabs132d,134dand136d.

The negative electrode tabs132e,134eand136emay be positioned on a line different from the line along which the plurality of positive electrode tabs132d,134dand136d. That is to say, the plurality of positive electrode tabs132d,134dand136dmay not be positioned along the line formed by the plurality of negative electrode tabs132e,134eand136e.

FIG. 5Ais a sectional view illustrating a coupled state of the secondary battery shown inFIG. 1A.

The plurality of positive electrode tabs132d,134dand136dare connected to the cap plate151, respectively. The plurality of positive electrode tabs132d,134dand136dmay penetrate the throughholes156aformed in the insulation case156to then be bent, respectively, and may be coupled to the bottom surface of the cap plate151.

The plurality of negative electrode tabs132e,134eand136emay penetrate the throughholes156bformed in the insulation case156to then be bent, respectively, and may be coupled to the bottom surface of the terminal plate155.

FIG. 5Bis a sectional view illustrating another example of a coupled state of the secondary battery shown inFIG. 1A.

The plurality of positive electrode tabs132d,134dand136dmay be stacked one on top of another to then be coupled to the cap plate151. The plurality of positive electrode tabs132d,134dand136dmay penetrate the throughholes156aformed in the insulation case156to then be bent, respectively, and may be coupled to the bottom surface of the cap plate151in a state where they are stacked one on top of another.

The plurality of negative electrode tabs132e,134eand136emay penetrate throughholes156bformed in the insulation case156to then be bent, respectively, and may be coupled to the bottom surface of the terminal plate155in a state where they are stacked one on top of another.

The secondary battery200according to the present embodiment is substantially the same as the secondary battery100shown inFIGS. 1 and 2, except for the configurations of the center pins240. Thus, the following description will focus on the center pins240. In addition, since the can120, the electrode assemblies130and the cap assembly150of the secondary battery200according to the illustrated embodiment of the present invention are formed in the same manner as corresponding ones of the previous embodiment shown inFIGS. 1 and 2, they will be identified by the same reference numerals, and detailed descriptions thereof will be omitted.

Referring toFIG. 3, each of the center pins240includes a blade241formed on its bottom surface. The blade241is formed such that the bottom of the center pin240is bent and faces outwardly.

The center pin240may be made of a metal. The blade241of the center pin240may be welded to the bottom of the can120. Since the blade241contacts the bottom of the can120with an increasing contact area, the center pin240can be more effectively supported, thereby improving coupling reliability.

A secondary battery according to another embodiment of the present invention will now be described.FIG. 4is a vertical section view illustrating a portion corresponding toFIG. 2in a secondary battery according to another embodiment of the present invention.

The secondary battery300according to the illustrated embodiment includes a can320, electrode assemblies130, a center pin340, and a cap assembly150.

The secondary battery300according to the present embodiment is substantially the same as the secondary battery100shown inFIGS. 1 and 2, except for configurations of the can320and the center pin340. Thus, the following description will focus on the can320and the center pin340. In addition, since the electrode assemblies130and the cap assembly150of the secondary battery300according to the illustrated embodiment of the present invention are formed in the same manner as corresponding ones of the previous embodiment shown inFIGS. 1 and 2, they will be identified by the same reference numerals, and detailed descriptions thereof will be omitted.

Referring toFIG. 4, the can320may have protruding parts321formed at its bottom surface. The protruding parts321may have a size and height large enough for the bottom portion of the center pin340to be engaged with and fixed. In addition, the number of the protruding parts321may correspond to that of the center-pins340. Since the center pin340is directly engaged with each of the protruding parts321, it can reduce a welding process for fixedly welding the can320and the center pin340to each other.

The center pin340may be shaped of a cylinder and made of a metallic or plastic material.

A secondary battery according to yet another embodiment of the present invention will now be described.

FIG. 6Ais a front view illustrating a plurality of electrode assemblies inserted into a can of a secondary battery according to yet another embodiment of the present invention.

The secondary battery400according to the illustrated embodiment of the present invention includes a can120, electrode assemblies130, center pins140, a connection tab460, an insulation case (not shown), and a cap plate (not shown).

In the illustrated secondary battery400, the electrode assemblies130are arranged in a manner different from those shown inFIGS. 1A through 2, and the connection tab460is additionally provided. Thus, the following description of the illustrated embodiment of the present invention will focus on the arranged state of the electrode assemblies130and the connection tab460. In addition, since the can120, the electrode assemblies130, the center pins140, the connection tab460, the insulation case (not shown) and the cap plate (not shown) of the illustrated secondary battery400are substantially the same as those of the previous embodiment shown inFIGS. 1A through 2, the same and corresponding functional components will be denoted by the same reference numerals and detailed descriptions thereof will not be given.

At least three lines of the plurality of electrode assemblies130may be aligned in a row, respectively. The illustrated embodiment of the present invention does not limit the number of lines of the electrode assemblies130to that illustrated herein.

The plurality of electrode assemblies130may be aligned such that a plurality of negative electrode tabs432e,432gand432iare aligned above the respective center pins140while a plurality of positive electrode tabs432d,432fand432hare aligned below the respective center pins140. Therefore, the positive electrode tabs432dof the electrode assemblies130positioned on the first line and the negative electrode tabs462gof the electrode assemblies130positioned on the second line alternately face each other.

The connection tab460may include negative electrode connection tabs460a,460cand460eand positive electrode connection tabs460b,460dand460f. The connection tab460may be shaped of a substantially rectangular plate. The connection tab460may be positioned on the insulation case (not shown). Here, the connection tab460can extend through the negative electrode connection tabs460a,460cand460e, the positive electrode connection tabs460b,460dand460f, and the insulation case (not shown) to be connected with the cap plate and terminal plate (?).

Specifically, the positive electrode connection tabs460b,460dand460fmay be connected to the positive electrode tabs432d,432fand432h, and the negative electrode connection tabs460a,460cand460eare connected to the negative electrode tabs432e,432gand432i. The positive electrode connection tabs460b,460dand460fand the positive electrode tabs432d,432fand432hmay be connected to each other to then be connected to the cap plate (not shown). The negative electrode connection tabs460a,460cand460eand the negative electrode tabs432e,432gand432imay be connected to each other to then be connected to the terminal plate (not shown).

In the present embodiment, the number of the connection tab460formed is six (6) in total. That is to say, each three connection tabs are formed, including three of the negative electrode connection tabs460a,460cand460eand three of the positive electrode connection tabs460b,460dand460f. However, the illustrated embodiment of the present invention does not limit the number of the connection tab460to that illustrated herein.

A secondary battery according to another embodiment of the present invention will now be described.

FIG. 6Bis a front view illustrating a plurality of electrode assemblies inserted into a can of a secondary battery according to another embodiment of the present invention.

The secondary battery500according to the illustrated embodiment of the present invention includes a can120, electrode assemblies130, center pins140, a connection tab560, an insulation case (not shown), and a cap plate (not shown).

In the illustrated secondary battery500, the electrode assemblies130are arranged in a different manner from those shown inFIGS. 1A through 2, and the connection tab560is additionally provided. Thus, the following description of the illustrated embodiment of the present invention will focus on the arranged state of the electrode assemblies130and the connection tab460. In addition, since the can120, the electrode assemblies130, the center pins140, the connection tab560, the insulation case (not shown) and the cap plate (not shown) of the illustrated secondary battery500are substantially the same as those of the previous embodiment shown inFIGS. 1A through 2, the same and corresponding functional components will be denoted by the same reference numerals and detailed descriptions thereof will not be given.

At least three lines of the plurality of electrode assemblies130may be aligned in a row. However, the illustrated embodiment of the present invention does not limit the number of lines of the electrode assemblies130to that illustrated herein.

The plurality of electrode assemblies130may be aligned such that positive electrode tabs532fand negative electrode tabs532gof the second line are aligned opposite to positive electrode tabs532dand532hand negative electrode tabs532eand532iof the first and third lines in view of the respective center pins140.

Therefore, the positive electrode tabs532dof the electrode assemblies130positioned on the first line and the positive electrode tabs532fof the electrode assemblies130positioned on the second line alternately face each other.

The connection tab560may include positive electrode connection tabs560band560dand negative electrode connection tabs560aand560c. The connection tab560may be shaped of a substantially rectangular plate. The connection tab560may be positioned on the insulation case (not shown). Here, the connection tab560may extend through the positive electrode tabs532d,532fand532hand the negative electrode tabs532e,532gand532i, and the insulation case (not shown) to be connected with the cap plate and terminal plate.

Specifically, the positive electrode connection tabs560band560dmay be connected to the positive electrode tabs532d,532fand532h, and the negative electrode connection tabs560aand560cmay be connected to the negative electrode tabs532e,532gand532i.

The positive electrode connection tabs560band560dand the positive electrode tabs532d,532fand532hmay be connected to each other to then be connected to the cap plate (not shown). The negative electrode connection tabs560aand560cand the negative electrode tabs532e,532gand532imay be connected to each other to then be connected to the terminal plate (not shown).

The number of the connection tab560formed may be four (4) in total. That is to say, each two connection tabs are formed, including two of the positive electrode connection tabs560band560dand two of the negative electrode connection tabs560aand560c. However, the illustrated embodiment of the present invention does not limit the number of the connection tab560to that illustrated herein.

The plurality of electrode assemblies130may be aligned such that the positive electrode tabs532fand the negative electrode tabs532gof the second line are aligned opposite to the positive electrode tabs532dand532hand the negative electrode tabs532eand532iof the first and third lines in view of the respective center pins140, so that corresponding parts of the electrode assemblies130have the same polarity, thereby reducing the number of the connection tab560.