Abstract:
A battery pack and a method of manufacturing the battery pack. An embodiment of a battery pack includes: a bare cell including an electrode assembly, a can containing the electrode assembly and having an opening at an end thereof for receiving the electrode assembly, and a cap plate sealing the opening; a protection circuit module for protecting the bare cell during charging; and a lead plate press-fit coupled to the cap plate and electrically connecting the bare cell to the protection circuit module.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/223,302 filed on Jul. 6, 2009, the entire content of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field 
     Aspects of embodiments of the present invention relate to a battery pack and a method of manufacturing the battery pack. 
     2. Description of the Related Art 
     A lithium ion battery pack typically includes a core pack that has a bare cell and a protection circuit module. 
     The bare cell includes a positive electrode plate, a negative electrode plate, electrolyte, and a separator for applying power to an external electronic device and enabling rechargeability. The protection circuit module protects the battery pack from over-charge and over-current and prevents performance degradation from over-discharge. 
     The bare cell and the protection circuit module are typically welded to a lead plate having a specific shape formed of metal, so that the bare cell can be electrically connected to the protection circuit module. 
     SUMMARY 
     According to an aspect of embodiments of the present invention, a battery pack includes a simple structure connecting a bare cell to a protection circuit module and that is configured to improve coupling strength between the bare cell and the protection circuit module. According to another aspect of embodiments of the present invention, a method of manufacturing a battery pack provides a battery pack including a simple structure connecting a bare cell to a protection circuit module and that is configured to improve coupling strength between the bare cell and the protection circuit module. 
     According to another aspect of embodiments of the present invention, a battery pack includes a lead plate having a simple L-shaped structure. 
     According to yet another aspect of embodiments of the present invention, a bare cell may be coupled to a protection circuit module in a simple manner where a recess corresponding to a lower part of the lead plate is formed in a cap plate of the bare cell, and the lead plate is press-fit coupled to the recess. 
     According to still another aspect of embodiments of the present invention, a portion surrounding the recess of the cap plate may be melted and coupled to the lead plate, thereby improving coupling strength between the bare cell and the lead plate. 
     According to an exemplary embodiment, a battery pack includes: a bare cell including an electrode assembly, a can containing the electrode assembly and having an opening at an end thereof for receiving the electrode assembly, and a cap plate sealing the opening; a protection circuit module for protecting the bare cell during charging; and a lead plate press-fit coupled to the cap plate and electrically connecting the bare cell to the protection circuit module. 
     The lead plate may include a first plate coupled to the protection circuit module and a second plate coupled to the cap plate. The first plate may be substantially perpendicular to the second plate. The lead plate may be L-shaped. In one embodiment, the lead plate is T-shaped. 
     In one embodiment, the cap plate has an outer surface facing the protection circuit module and a recess on the outer surface, and an end portion of the second plate is inserted in and press-fit coupled to the recess. A portion of the cap plate adjacent the recess may be welded to the second plate. In one embodiment, a portion of the cap plate adjacent the recess is resistance welded or seam welded to the second plate such that the portion of the cap plate adjacent the recess or a portion of the second plate is melted and fills a gap between the end portion of the second plate and the cap plate in the recess. 
     In one embodiment, the end portion of the second plate is coupled to the cap plate at the recess via a conductive material. The conductive material may include an adhesive. 
     In one embodiment, the first plate is soldered to the protection circuit module. 
     In one embodiment, the lead plate is press-fit coupled to a first side of the cap plate, and the battery pack further includes another lead plate press-fit coupled to a second side of the cap plate and connecting the bare cell to the protection circuit module, the second side of the cap plate being distal from the first side. The cap plate may have another recess on the outer surface at the second side, and the another lead plate may be press-fit coupled to the another recess. The lead plate and the another lead plate may be positive electrode lead plates. The lead plate may be a positive electrode lead plate and the another lead plate may be a dummy lead plate. 
     In one embodiment, the protection circuit module has a penetration hole. 
     In one embodiment, the bare cell further includes an electrode terminal protruding through an aperture in the cap plate and electrically connecting the electrode assembly to the protection circuit module. 
     According to another exemplary embodiment, a method of manufacturing a battery pack having a bare cell having an electrode assembly and a can containing the electrode assembly and having an opening at an end thereof for receiving the electrode assembly includes: sealing the opening of the can with a cap plate; and electrically connecting a protection circuit module to the bare cell for protecting the bare cell during charging by press-fit coupling a lead plate to the cap plate. 
     Electrically connecting a protection circuit module to the bare cell may include soldering a first plate of the lead plate to the protection circuit module and press-fit coupling an end portion of a second plate of the lead plate to a recess on an outer surface of the cap plate. Electrically connecting a protection circuit module to the bare cell may further include resistance welding or seam welding a portion of the cap plate adjacent the recess to the second plate such that the portion of the cap plate adjacent the recess or a portion of the second plate is melted and fills a gap between the end portion of the second plate and the cap plate in the recess. 
     In one embodiment, the method further includes applying a conductive adhesive to a portion of the lead plate that is press-fit coupled to the cap plate. 
     These and/or other features and aspects of the present invention will become apparent and more readily appreciated from the following description of some exemplary embodiments, taken in conjunction with the accompanying drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of a battery pack according to an embodiment of the present invention. 
         FIG. 2  is an exploded view of a bare cell of a battery pack according to an embodiment of the present invention. 
         FIG. 3  is a partial front view of the battery pack of  FIG. 1 . 
         FIG. 4  is an enlarged partial perspective view of the battery pack of  FIG. 1 . 
         FIGS. 5 and 6  are enlarged partial perspective views of a battery pack according to another embodiment of the present invention. 
         FIG. 7  is a perspective view of a lead plate of a battery pack according to another embodiment of the present invention. 
         FIG. 8  is a perspective view of a lead plate of a battery pack according to another embodiment of the present invention. 
         FIG. 9  is a perspective view of a lead plate of a battery pack according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Some exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, the present invention may be embodied in different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided for reasons of disclosure to convey the scope of the invention to those skilled in the art. Like reference numerals denote like elements throughout. 
     Hereinafter, a battery pack and a method of manufacturing the battery pack will now be described with reference to the accompanying drawings according to some exemplary embodiments. 
       FIG. 1  is an exploded view of a battery pack according to an embodiment of the present invention.  FIG. 2  is an exploded view of a bare cell of a battery pack according to an embodiment of the present invention.  FIG. 3  is a partial front view of the battery pack of  FIG. 1 . 
     Referring to  FIG. 1 , a battery pack  10  according to one embodiment of the present invention includes a bare cell  100 , a protection circuit module  200 , and first and second L-shaped lead plates  310  and  330  electrically and mechanically connecting the bare cell  100  to the protection circuit module  200 . In one embodiment, a cap plate  151  of the bare cell  100  includes first and second recesses  151   a  and  151   b  at positions respectively corresponding to the first and second lead plates  310  and  330 . The recesses  151   a  and  151   b , in one embodiment, have shapes corresponding to the lower parts of the first and second lead plates  310  and  330 , and the first and second lead plates  310  and  330  are press-fit coupled to the recesses  151   a  and  151   b  of the cap plate  151 . In one embodiment, portions of the cap plate  151  surrounding the recesses  151   a  and  151   b  are melted and coupled to the first and second lead plates  310  and  330 , so as to increase coupling strength of the bare cell  100  and the first and second lead plates  310  and  330 . 
     Referring to  FIGS. 1 and 2 , the bare cell  100 , in one embodiment, includes a can  110 , an electrode assembly  130  disposed in the can  110 , and a cap assembly  150  closing a top opening  110   a  of the can  110 . 
     The can  110 , having a generally rectangular parallelepiped shape in one embodiment, may have the top opening  110   a  at a side other than the top. The can  110  may be formed of a metal, or any other suitable material, and function as a terminal. The electrode assembly  130  described later herein may be inserted through the top opening  110   a  of the can  110 . 
     The electrode assembly  130 , in one embodiment, includes a first electrode plate  132 , a second electrode plate  134 , and a separator  136  that may be wound together in a jelly roll shape. The separator  136 , in one embodiment, is disposed between the first electrode plate  132  and the second electrode plate  134 . 
     The first electrode plate  132  may include a first electrode collector (not shown) and a first electrode coating portion (not shown). A first electrode tab  132   a  may be attached to a side of the first electrode collector and protrude to the top opening  110   a  of the can  110 . 
     The second electrode plate  134  may include a second electrode collector (not shown) and a second electrode coating portion (not shown). A second electrode tab  134   a  may be attached to a side of the second electrode collector and protrude to the top opening  110   a  of the can  110 . The second electrode tab  134   a  may be made from copper (Cu) or nickel (Ni). In one embodiment, the first electrode plate  132  is a positive electrode, and the second electrode plate  134  is a negative electrode. In another embodiment, the first electrode plate  132  is a negative electrode, and the second electrode plate  134  is a positive electrode. Hereinafter, embodiments of the present invention will be described with reference to the first electrode plate  132  being a positive electrode and the second electrode plate  134  being a negative electrode. 
     The separator  136  may include a porous film made from polyethylene (PE), polypropylene (PP), a combination thereof, or any other suitable material. The separator  136 , disposed in the electrode assembly  130 , is configured to prevent or substantially prevent electric conduction between the first electrode plate  132  and the second electrode plate  134  and improve mobility of lithium ions. The separator  136  is further configured to prevent or substantially prevent the first electrode plate  132  from contacting the second electrode plate  134 . In addition, if the temperature of the battery pack  10  is increased by an external short circuit, the separator  136  may prevent or substantially prevent further temperature increase of the battery pack  10  through a shut-down operation. 
     The cap assembly  150 , in one embodiment, includes the cap plate  151 , an insulation plate  152 , a terminal plate  153 , an electrode terminal  154 , and a gasket  155 . The cap assembly  150 , in one embodiment, is coupled with an insulation case  156  to the electrode assembly  130  at the top opening  110   a  of the can  110  to seal the can  110 . 
     A terminal through hole  151   c , in one embodiment, is disposed at or near the middle, or at another suitable region, of the cap plate  151 . An electrolyte injection hole (not shown) may also be disposed in the cap plate  151 . In one embodiment, a safety vent (not shown) is disposed at a surface of the cap plate  151  corresponding to the electrolyte injection hole with respect to the terminal through hole  151   c . After electrolyte is injected or otherwise put into the can  110 , the electrolyte injection hole may be covered with a cover (not shown), such as a ball. The first electrode tab  132   a  may be electrically connected to a side of the cap plate  151  corresponding to the first electrode tab  132   a . Thus, the cap plate  151  and the can  110  contacting the cap plate  151  may include the positive pole. The cap plate  151 , in one embodiment, includes a metal plate having a size corresponding to the top opening  110   a  of the can  110 . In one embodiment, the first and second recesses  151   a  and  151   b , respectively coupled to the first and second lead plates  310  and  330 , are disposed at both sides of the cap plate  151 . The first and second recesses  151   a  and  151   b  will be described later herein in further detail. 
     The insulation plate  152 , in one embodiment, is coupled to a lower surface of the cap plate  151 , and is formed of an insulation material, such as an insulative material that forms the gasket  155 . The terminal plate  153 , in one embodiment, is coupled to a lower surface of the insulation plate  152  and is formed of nickel alloy, or any other suitable material. The insulation plate  152  and the terminal plate  153 , in one embodiment, are provided with through holes  152   a  and  153   a , respectively, corresponding to the terminal through hole  151   c  of the cap plate  151  and at positions corresponding to the terminal through hole  151   c  of the cap plate  151 . 
     The electrode terminal  154 , in one embodiment, is inserted through the terminal through holes  151   c ,  152   a ,  153   a  of the cap plate  151 , the insulation plate  152 , and the terminal plate  153  and is electrically connected to the second electrode tab  134   a  of the electrode assembly  130 . Thus, the electrode terminal  154  may include the negative pole. 
     When the electrode terminal  154  is inserted into the terminal through hole  151   c  of the cap plate  151 , the gasket  155  may be disposed between the electrode terminal  154  and the cap plate  151  to insulate the electrode terminal  154  and the cap plate  151  from each other. 
     With further reference to  FIGS. 1 and 3 , the protection circuit module  200 , in one embodiment, includes a substrate  210 , a protection circuit part (not shown), a charge/discharge terminal  220 , a positive temperature coefficient (PTC) device  230 , the first lead plate  310 , the second lead plate  330 , and a third lead plate  350 . The protection circuit module  200  may include a conductive metal pattern (not shown) on the substrate  210 . Additionally, in one embodiment, the protection circuit module  200  has a penetration hole  240  formed through the substrate  210  for facilitating connecting (e.g., by welding) of the third lead plate  350  to the electrode terminal  154 . 
     The protection circuit module  200 , in one embodiment, is disposed on the cap plate  151  to protect the bare cell  100  from over-charge and over-current, and to prevent or substantially prevent performance degradation from over-discharge. The protection circuit module  200 , in one embodiment, may include the first lead plate  310 , the second lead plate  330 , and the third lead plate  350 , and in another embodiment, may not include one or more of the first lead plate  310 , the second lead plate  330 , and the third lead plate  350 . Hereinafter, the first lead plate  310 , the second lead plate  330 , and the third lead plate  350  are described separately, or independently, of the protection circuit module  200 . 
     The substrate  210  may include a conductive metal pattern (not shown) mounted thereon, and a plurality of thin substrates stacked thereon. The substrate  210  may be formed of epoxy or Bakelite-based material. The conductive metal pattern may be electrically connected to the protection circuit part, the charge/discharge terminal  220 , the first lead plate  310 , the second lead plate  330 , and the PTC device  230 . 
     The protection circuit part, in one embodiment, is configured to check information about the charge/discharge state, current, voltage, and temperature of a battery to protect the battery. 
     The charge/discharge terminal  220  is electrically connected to the protection circuit part and the conductive metal pattern to electrically communicate with an external device. 
     The PTC device  230 , in one embodiment, is disposed under the substrate  210  and is electrically connected to the electrode terminal  154  of the bare cell  100  through the third lead plate  350 . The PTC device  230 , in one embodiment, is configured such that when the temperature of the battery pack  10  is greater than a reference temperature (e.g., a critical temperature), the electrical resistance of the PTC device  230  becomes infinite. Thus, when the temperature of the battery pack  10  is greater than the reference temperature, the PTC device  230  limits a charge/discharge current of the battery pack  10 . 
     The first and second lead plates  310  and  330 , respectively disposed on both lower sides of the substrate  210  in one embodiment, electrically and mechanically connect the cap plate  151  of the bare cell  100  to the protection circuit module  200 . The first and second lead plates  310  and  330 , in one embodiment, are positive electrode lead plates. In this case, the first and second lead plates  310  and  330  electrically connect the bare cell  100  to the protection circuit module  200 . Alternatively, one of the first and second lead plates  310  and  330  may be a positive electrode lead plate, and the other may be a dummy lead plate. In this case, the dummy lead plate spaces the bare cell  100  apart from the protection circuit module  200  without electrically connecting the bare cell  100  to the protection circuit module  200 . Hereinafter, the first and second lead plates  310  and  330  are described as being positive electrode lead plates. However, in the embodiment where only one of the first and second lead plates  310  and  330  is a positive electrode lead plate, a dummy lead plate may have the same configuration as the positive electrode lead plate except that the dummy lead plate is not electrically connected to the conductive metal pattern of the protection circuit module  200 . 
     In one embodiment, the first lead plate  310  includes a first plate  312  and a second plate  314 , and the second lead plate  330  includes a first plate  332  and a second plate  334 . In one embodiment, the first plate  312  of the first lead plate  310  is soldered to one side of the protection circuit module  200 , and the second plate  314  is connected to one side of the first plate  312  and electrically connected to one side of the cap plate  151 . Similarly, the first plate  332  of the second lead plate  330  may be soldered to one side of the protection circuit module  200 , and the second plate  334  may be connected to one side of the first plate  332  and electrically connected to one side of the cap plate  151 . In more detail, the first plates  312  and  332  and the second plates  314  and  334 , in one embodiment, may be formed as tetragonal flat plates, and the second plates  314  and  334  may be bent or otherwise extended toward the bare cell  100  perpendicular or substantially perpendicular to the first plates  312  and  332 . The lower parts of the second plates  314  and  334  are respectively coupled to the first and second recesses  151   a  and  151   b  of the cap plate  151  which correspond to the lower parts of the second plates  314  and  334 . That is, in one embodiment, the lower part of the second plate  314  of the first lead plate  310  is a first coupling part  314   a , and the lower part of the second plate  334  of the second lead plate  330  is a second coupling part  334   a . The first plates  312  and  332  and the second plates  314  and  334 , in one embodiment, are formed of a metal, such as nickel or nickel alloy, but alternatively, may be formed of any other suitable metal or other material. 
     The third lead plate  350 , in one embodiment, electrically connects the electrode terminal  154  disposed over the bare cell  100  to the PTC device  230  disposed under the protection circuit module  200 . The third lead plate  350  may be a negative electrode lead plate. 
     Hereinafter, the coupling of the first and second lead plates  310  and  330  to the cap plate  151  will be described in further detail. The coupling of the first lead plate  310  and the first recess  151   a  may be the same or substantially similar to that of the second lead plate  330  and the second recess  151   b . Therefore, the coupling of the first lead plate  310  to the first recess  151   a  will now be representatively described, and the coupling of the second lead plate  330  to the second recess  151   b  will be omitted. 
       FIG. 4  is a partial enlarged perspective view of the battery pack of  FIG. 1 . 
     Referring to  FIG. 4 , the first lead plate  310  of the battery pack  10 , in one embodiment, includes the first plate  312  electrically connected to one side of the lower surface of the substrate  210  of the protection circuit module  200 , and the second plate  314  connected to one side of the first plate  312  and electrically connected to one side of the cap plate  151 . In particular, the first and second plates  312  and  314  may have tetragonal flat plate shapes, and the second plate  314  may be bent or otherwise extended toward the bare cell  100  to be perpendicular or substantially perpendicular to the first plate  312 . 
     The first lead plate  310 , as described above, has a simple structure for connecting the protection circuit module  200  to the bare cell  100 . In particular, since the number of plates constituting the first lead plate  310  is only two, the first lead plate  310  has a simple structure. Thus, manufacturing of the first lead plate  310  is easy, and the protection circuit module  200  is coupled to the bare cell  100  utilizing a simple structure. However, the present invention is not limited to embodiments in which a first lead plate and a second lead plate each consist of two plates, but alternatively, may encompass embodiments in which one or more of the lead plates is formed of a single plate or includes three or more plates. 
     The first recess  151   a  may be disposed at one side of the cap plate  151  and, in one embodiment, has a shape corresponding to the lower part of the second plate  314 , that is, to the first coupling part  314   a . In one embodiment, the first recess  151   a  may have a generally rectangular parallelepiped shape in a three-dimensional view and a rectangular shape in a two dimensional view. The first coupling part  314   a  of the first lead plate  310 , in one embodiment, is mechanically and electrically connected to the first recess  151   a  of the cap plate  151  through press-fit coupling. As such, the length and width of the first coupling part  314   a , in one embodiment, correspond to those of the first recess  151   a , and the first coupling part  314   a  is press-fit coupled into the first recess  151   a . The frictional force due to the press-fit coupling prevents or substantially prevents the first coupling part  314   a  from being removed from the first recess  151   a.    
     The press-fit coupling of the first coupling part  314   a  in the first recess  151   a  and the second coupling part  334   a  in the second recess  151   b  may substitute for or supplement the lead plates being coupled to a cap plate through laser welding or other methods or configurations wherein a jig may be needed to remove a gap between the upper surface of the cap plate and the lead plate. Further, embodiments of the present invention may reduce or prevent the protection circuit module from being broken by the pressure of the jig, a welding part of the lead plate being spaced apart from the cap plate to cause welding defects, and/or alignment issues or other difficulties caused by welding. 
     In the battery pack  10 , when the protection circuit module  200  is coupled to the bare cell  100 , the first and second lead plates  310  and  330 , having simple structures, are press-fit coupled to the bare cell  100 . Accordingly, a jig pressing process is not required, resulting in a simple and efficient manufacturing process. Also, because a welding process that may cause defects may be removed or replaced with a reliable welding process, manufacturing costs can be reduced, and productivity can be improved. 
     The first coupling part  314   a  may be coupled to the first recess  151   a  through conductive adhesive that improves electrical conductivity between the cap plate  151  and the first lead plate  310  to reduce electrical resistance between the bare cell  100  and the protection circuit module  200  and that improves mechanical coupling between the first lead plate  310  and the cap plate  151 . That is, in one embodiment, a conductive adhesive, or alternatively a non-conductive adhesive, may be applied between the first coupling part  314   a  and the first recess  151   a  to improve mechanical coupling strength (e.g., together with the press-fit coupling described above) and/or to reduce electrical resistance. Similarly, the second coupling part  334   a  may be coupled to the second recess  151   b  utilizing a conductive adhesive. The conductive adhesive may be AL30FR manufactured by 3M or any other suitable adhesive, and may have a thickness of 0.08 mm or any other suitable thickness. 
       FIGS. 5 and 6  are enlarged partial perspective views of a battery pack according to another embodiment of the present invention. 
     Referring to  FIGS. 5 and 6 , a battery pack  20  according to one embodiment of the present invention is the same or similar to the battery pack  10  described above except that the first lead plate  310  is press-fit coupled to the first recess  151   a , and additionally, a portion  151   d  of the cap plate  151  around or surrounding the first recess  151   a  is melted and welded to the first lead plate  310 . Therefore, only the difference between the battery pack  20  and the battery pack  10  will now be described in further detail, and other aspects of the above-described battery pack  10  will not be described again herein. Furthermore, the coupling of the second lead plate  330  and the second recess  151   b  in the battery pack  20  may be the same or substantially similar to that of the first lead plate  310  and the first recess  151   a . Therefore, the coupling of the first lead plate  310  to the first recess  151   a  will now be representatively described, and the coupling of the second lead plate  330  to the second recess  151   b  will be omitted. 
     In the battery pack  20 , the first coupling part  314   a  of the first lead plate  310  may be press-fit coupled to the first recess  151   a , as described in the previous embodiments. Thereafter, in one embodiment, a current is applied to the portion  151   d  of the cap plate  151  to melt the portion  151   d , and the cap plate  151  is welded to the second plate  314  through resistance welding, and particularly, through seam welding. In seam welding, a current is briefly applied to a region to be welded, and the resistance heat of a contact melts the region to be welded. At this point, a seam is continuously formed in the region to be welded. 
     Referring again to  FIGS. 5 and 6 , when a strong current is applied to the portion  151   d  of the cap plate  151  or to an upper portion  314   b  of the first coupling part  314   a  of the second plate  314 , the portion  151   d  is melted and welded to the upper portion  314   b  of the first coupling part  314   a  of the second plate  314 , or the upper portion  314   b  of the first coupling part  314   a  is melted and welded to the portion  151   d , thereby improving the coupling strength between the first lead plate  310  and the cap plate  151 . At this point, a melted portion of the portion  151   d  or the upper portion  314   b  of the first coupling part  314   a  fills a gap between the first recess  151   a  and the first coupling part  314   a  coupled to the first recess  151   a , thereby further improving the coupling strength between the first lead plate  310  and the cap plate  151 . In  FIG. 6 , a region A denotes a welded region between the first lead plate  310  and the cap plate  151 . 
       FIG. 7  shows a lead plate  410  of a battery pack according to another embodiment of the present invention. As with the lead plate  310  described above, the lead plate  410  may be used in combination with one or more lead plates having a different configuration or as one of a pair, wherein the other lead plate has the same configuration. 
     The lead plate  410  differs from the lead plates of the previous embodiments in that it has a substantially T-shaped profile. In one embodiment, the stem of the “T” is formed by a second plate  414  having substantially the same configuration as that of the second plate  314  described above. The second plate  414 , in one embodiment, engages with a recess  151   a ,  151   b  of the cap plate  151  in the same manner as described above with respect to the lead plate  310  and, therefore, a description thereof will not be repeated. 
     In one embodiment, the cross-bar of the “T” is defined by two sub-plates  412   a  and  412   b . The sub-plates are formed by dividing a first plate  412  of the lead plate  410  in half and bending the two halves in opposite directions. 
     The first plate  412  of the lead plate  410  functions as a support portion in the same manner as described above with respect to the lead plate  310 . Further, in one embodiment, the first plate  412  is soldered to the side of the protection circuit module  200  that faces the bare cell  100  in a similar or same manner as in the above-described embodiments, although the distribution of the solder will be different to take account of the different shape offered by the surface area of the lead plate  412 . 
       FIG. 8  shows a lead plate  510  according to another embodiment of the present invention. The lead plate  510  is similar to the lead plate  410  shown in  FIG. 7 , but the cross-bar of the “T” is, in one embodiment, formed by three sub-plates  512   a ,  512   b , and  512   c  extending from a second plate  514 . These sub-plates are formed, in one embodiment, by dividing the first plate  512  using two cuts and then bending the first and third sub-plates  512   a ,  512   c  in one direction, and bending the second sub-plate  512   b  in an opposite direction. The lead plate  510  may, like in other embodiments, be used with differently configured lead plates, or as one of a matching pair. Further, the lead plate  510  may be connected to the protection circuit module  200  and the bare cell  100  in the same manner as the lead plate  410  shown in  FIG. 7 . 
       FIG. 9  shows a lead plate  610  according to another embodiment of the present invention. The lead plate  610  is similar to the lead plates  410  and  510  shown in  FIGS. 7 and 8  in that it has a T-shaped profile. A second plate  614 , in one embodiment, is the same as that of the lead plates  410  and  510  and is attached to the cap plate  151  in the same manner as that of the lead plates  410  and  510  and, therefore, a description thereof will not be repeated. 
     The cross member of the “T” of the lead plate  610  is formed by a first plate  612  that is formed by using two bends. In one embodiment, the lead plate material is bent 90° toward a first direction (e.g., the right side in  FIG. 9 ), and the bent portion is then bent back upon itself through 180° about a bend line  612   f . The resulting structure has a first plate  612  formed from a lower sub-plate  612   e  and an upper sub-plate  612   d  that has approximately twice the length of the lower sub-plate  612   e.    
     As with the lead plates of other embodiments described herein, the lead plate  610  may be used in combination with lead plates having different configurations or as one of a matching pair. The first plate  612  may be coupled to the protection circuit module  200  using a soldering process, as with the other embodiments described above. 
     Some exemplary embodiments have been described herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purposes of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.