Abstract:
A battery includes a case having an opening, an electrode assembly disposed in the case and having first and second electrode tabs extending therefrom, and a cap assembly covering the opening in the case, the cap assembly including an insulation case disposed adjacent to the electrode assembly, the insulation case having an anti-deformation portion and first and second electrode tab holes, wherein the first and second electrode tabs extend through the first and second electrode tab holes, respectively.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a battery. More particularly, the present invention relates to a battery configured to tolerate compression applied thereto, and a method of making the same.  
         [0003]     2. Description of the Related Art  
         [0004]     Recently, compact and light electrical/electronic devices, including, e.g., cellular phones, laptop computers, camcorders, etc., have been actively developed and produced. These portable devices may be equipped with a battery pack so that they can be operated when a separate power supply is unavailable. The battery pack may contain one or more batteries that output a predetermined level of voltage, so that the portable devices can be powered for a predetermined period of time without being connected to the separate power supply.  
         [0005]     Battery types generally include primary, or single-use, and secondary, or rechargeable, batteries. Secondary batteries offer an economical way to provide portable devices with power, since they can be recharged multiple times. Examples of electrochemical technologies employed in secondary batteries include, e.g., nickel-cadmium (Ni—Cd) batteries, nickel metal hydride (Ni-MH) batteries, lithium (Li) batteries, lithium ion batteries, etc.  
         [0006]     For lithium-based secondary batteries, lithium-based oxide and carbon are commonly used as the electrode positive and negative active materials, respectively. Lithium secondary batteries may be generally classified, based on the type of electrolyte employed, into lithium ion batteries, which use a liquid electrolyte, and lithium polymer batteries, which use a polymer electrolyte. In addition, lithium secondary batteries may be manufactured in various form factors, e.g., cylindrical, prismatic, pouch, etc.  
         [0007]     Lithium-based secondary batteries may exhibit an operating voltage of about 3.6V, which is generally three times greater than that of comparable Ni—Cd batteries or Ni-MH batteries. Lithium-based batteries may also exhibit a high energy density per unit weight. For these reasons, they are increasingly used in the industry.  
         [0008]     Batteries, particularly those having a high energy density and/or a high operating voltage, may present risks to the device being powered and/or people if the batteries become damaged. For example, if the battery is damaged, battery electrodes inside the battery may short-circuit, which may cause, e.g., rapid heat buildup, leakage, fire, explosion, etc.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention is therefore directed to a battery and a method of making the same, which substantially overcome one or more of the problems due to the limitations and disadvantages of the related art.  
         [0010]     It is therefore a feature of an embodiment of the present invention to provide a battery having an insulation case through which an electrode tab passes, the insulation case configured to resist deformation when the battery is subjected to an externally-applied compressive force.  
         [0011]     It is therefore another feature of an embodiment of the present invention to provide a battery having an insulation case that includes an anti-deformation portion disposed adjacent to an electrode tab hole in the insulation case, the anti-deformation portion helping to prevent deformation of the electrode tab hole.  
         [0012]     At least one of the above and other features and advantages of the present invention may be realized by providing a battery including a case having an opening, an electrode assembly disposed in the case and having first and second electrode tabs extending therefrom, and a cap assembly covering the opening in the case, the cap assembly including an insulation case disposed adjacent to the electrode assembly, the insulation case having an anti-deformation portion and first and second electrode tab holes, wherein the first and second electrode tabs extend through the first and second electrode tab holes, respectively.  
         [0013]     The battery may further include an electrode terminal welded to the first electrode tab, the electrode terminal passing through the cap assembly. The first electrode tab hole may define an opening through which the first electrode tab passes, the opening having an area substantially larger than a cross-sectional area of the first electrode tab, such that the first electrode tab may be spaced apart from a periphery of the opening when the first electrode tab is inserted through the opening. The anti-deformation portion may include a support piece disposed on a side of the first electrode tab hole. The support piece may connect a side of the first electrode tab hole to an opposite side of the first electrode tab hole so as to divide the first electrode tab hole into two parts. The anti-deformation portion may further include a reinforcement rib disposed along at least a part of a periphery of the first electrode tab hole.  
         [0014]     The anti-deformation portion may include a reinforcement rib disposed along at least a part of a periphery of the first electrode tab hole. The insulation case may have a rib extending along a periphery thereof, and the rib and the reinforcement rib may have a same height. An anti-deformation portion may be provided for each of the first and second electrode tab holes. The battery case may be a prismatic case.  
         [0015]     At least one of the above and other features and advantages of the present invention may be realized by providing a battery including a case having an opening, an electrode assembly disposed in the case and having at least one electrode tab extending therefrom, and a cap assembly covering the opening in the case, the cap assembly including an insulation case disposed adjacent to the electrode assembly, the insulation case having an electrode tab hole therein, the at least one electrode tab extending through the electrode tab hole, wherein the insulation case includes a means for preventing deformation of the electrode tab hole disposed at a periphery of the electrode tab hole.  
         [0016]     The means for preventing deformation of the electrode tab hole may prevent elongation of the electrode tab hole. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:  
         [0018]      FIG. 1  illustrates an exploded perspective view of a battery according to an embodiment of the present invention;  
         [0019]      FIG. 2  illustrates a top plan view of an insulation case of the battery of  FIG. 1 ;  
         [0020]      FIG. 3  illustrates a sectional view of the assembled battery of  FIG. 1 ;  
         [0021]      FIG. 4  illustrates a top plan view of an insulation case of a battery according to another embodiment of the present invention; and  
         [0022]      FIG. 5  illustrates a sectional view taken along line V-V of  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Korean Patent Application No. 2006-0003251, filed on Jan. 11, 2006, in the Korean Intellectual Property Office, and entitled: “Secondary Battery,” is incorporated by reference herein in its entirety.  
         [0024]     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.  
         [0025]     In the figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred-to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout.  
         [0026]     A battery according to an embodiment of the present invention will be now be described. In the description that follows, particular examples will be referred to in order to provide a clear understanding of the present invention. However, it will be appreciated that embodiments of the present invention are not restricted to these particular examples. Thus, for example, aspects of the following description describe a prismatic secondary battery. However, embodiments of the present invention are not limited thereto, and may be applied to, e.g., primary batteries, cylindrical batteries, etc.  
         [0027]      FIG. 1  illustrates an exploded perspective view of a battery according to an embodiment of the present invention,  FIG. 2  illustrates a top plan view of an insulation case of the battery of  FIG. 1 , and  FIG. 3  illustrates a sectional view of the assembled battery of  FIG. 1 . Referring to  FIGS. 1-3 , a battery may be a bare cell including a case  200 , an electrode assembly  250  contained inside the case  200 , and a cap assembly  100  coupled to an opening  201  of the case  200  to seal the top of the case  200 . The battery may be, e.g., a secondary battery.  
         [0028]     The battery case  200  may be metal, e.g., aluminum or aluminum alloy, and may be rectangular. The electrode assembly  250  may be placed into the case  200  via the opening  201 . The case  200  may act as an electrode terminal, i.e., it may be connected to one of a first and second electrode tab  215  and  225  of the electrode assembly  250 .  
         [0029]     The electrode assembly  250  may be, e.g., a lamination of a first electrode  210 , one or more separators  230 , and a second electrode  220 . The electrodes  210  and  220 , and the separator(s)  230 , may be wound into a spiral.  
         [0030]     The first electrode  210  may be connected to the first electrode tab  215 . The second electrode  220  may be connected to the second electrode tab  225 . The first and second electrodes  210  or  220  may act as negative and positive electrodes, respectively, although they may be switched depending on the implementation.  
         [0031]     Where configured as the negative electrode, the first electrode  210  may be a thin plate or film type electrode, and may include a current collector made of conductive metal foil, e.g., a copper foil, and an active material layer coated on both surfaces of the collector using, e.g., carbon as the main component. The first electrode tab  215 , which may be a negative electrode tab, may be connected to a region of the first electrode  210  which has no active material thereon. The first electrode tab  215  may be extended upwards from the first electrode  210 , i.e., towards the cap assembly  100 .  
         [0032]     Where configured as the positive electrode, the second electrode  220  may include a current collector made of metal foil having excellent electrical conductivity, e.g., aluminum foil, and an active material layer coated on both surfaces of the collector using, e.g., a lithium-based oxide as the main component. The second electrode tab  225 , which may be a positive electrode tab, may be electrically connected to a region of the second electrode  220  which has no positive electrode active material thereon. The second electrode tab  225  may be extended upwards from the second electrode  220 .  
         [0033]     The separator  230  may be made of an insulator, e.g., polyethylene, polypropylene, a copolymer of polyethylene and polypropylene, etc. The separator  230  may have a width larger than the width of the first and second electrodes  210  and  220 , which may help avoid a short circuit between the first and second electrodes  210  and  220 .  
         [0034]     The cap assembly  100  may be adapted to close and seal the opening  201  of the case  200 . The cap assembly  100  may include a flat cap plate  110  having a size and a shape corresponding to the size and shape of the opening  201 . The cap assembly  100  may also include an insulation plate  140  positioned adjacent to the lower surface of the cap plate  110 , and a terminal plate  150  positioned adjacent to the lower surface of the insulation plate  140 . The terminal plate  150  may be electrically connected to the first electrode tab  215  and, thus, to the first electrode  210 .  
         [0035]     The cap plate  110  may have a first terminal hole  111  formed therein, e.g., in the center thereof, in order to accommodate a first electrode terminal  130 . The first electrode terminal  130  may extend through the cap plate  110  and may be connected to the first electrode tab  215 . A tubular gasket  120  may be positioned in the first terminal hole  111  and around the first electrode terminal  130 , in order to electrically insulate the first electrode terminal  130  from the cap plate  110 .  
         [0036]     The cap plate  110  may have an electrolyte injection hole  113  formed therein, e.g., at a side thereof. The electrolyte injection hole  113  may be used to inject electrolyte into the interior of the battery after the cap assembly  100  is assembled to the opening  201  of the case  200 . After the electrolyte is injected, the electrolyte injection hole  113  may be sealed by a plug  115 .  
         [0037]     The insulation plate  140  may be made of a same insulation material as the gasket  120 . The insulation plate  140  may be coupled to the lower surface of the cap plate  110  and may have a second terminal hole  141  formed therein that corresponds to and communicates with the first terminal hole  111  in the cap plate  110 .  
         [0038]     The terminal plate  150  may be made of a metal, e.g., nickel (Ni) metal or a Ni alloy, and may be coupled to the lower surface of the insulation plate  140 . The terminal plate  150  may have a third terminal hole  151  formed therein that corresponds to the first terminal through  111  in the cap plate  110 .  
         [0039]     The insulation case  160  may be positioned on top of the electrode assembly  250  to insulate the electrode assembly  250  from the cap plate  110 .  
         [0040]     The insulation case  160  may be made of a high-molecular resin having insulation properties, e.g., polypropylene. The insulation case  160  may have first and second electrode tab holes  163  and  165  located such that the respective first and second electrode tabs  215  and  225  can project from the top of the electrode assembly  250  through the holes  163  and  165 .  
         [0041]     The insulation case  160  may have an electrolyte injection hole  161  formed therein, e.g., at a side thereof. The electrolyte injection hole  161  may be aligned with the electrolyte injection hole  113  that is formed in the cap plate  110 .  
         [0042]     One of the first and second electrode tabs  215  and  225  may act as a negative electrode tab. For example, the first electrode tab  215  may act as the negative electrode tab.  
         [0043]     Assembly of the battery may require that the first electrode tab  215  be welded to the first electrode terminal  130 . To this end, the first electrode tab hole  163 , through which the first electrode tab  215  extends, may be configured to have a size large enough to enable the electrode terminal  130  and the first electrode tab  215  to be welded to each other after installation of the insulation case  160 . Therefore, the first electrode tab hole  163  may have a size larger than is required merely to accommodate the first electrode tab  215 . The second electrode tab hole  165  may be similarly sized with respect to the second electrode tab  225 .  
         [0044]     During assembly of the battery, e.g., when the cap assembly  110  is pressed against the case  200  to seal it, or during use of the battery by an end user, an externally-applied compressive force may be applied to the battery. Such a force, if applied to the first and/or second electrode tabs  215  and  225 , may have a tendency to cause the first and second electrode tab holes  163  and  165  to deform, e.g., to enlarge. This may allow the first and second electrode tabs  215  and  225 , which extend through the first and second electrode tab holes  163  and  165 , to be displaced in the reverse direction, i.e., inwardly, which may result in an undesired electrical contact with the case  200 , the electrode assembly  250 , etc. For example, the compressive force could cause the first and/or second electrode tabs  215  and  225  to short-circuit to the case  200  and/or electrode assembly  250  if they are displaced inwardly through the first and second electrode tab holes  163  and  165 .  
         [0045]     Accordingly, in the battery according to this embodiment of the present invention, one or both of the first and second electrode tab holes  163  and  165  may be provided with an anti-deformation portion, in order to reduce or eliminate the possibility of the holes  163  and  165  becoming deformed. The anti-deformation portion may include a support piece  167  as a feature for reducing the size of the first and second electrode tab holes  163  and  165 .  
         [0046]     In the case of the first electrode tab hole  163 , as shown in  FIG. 2 , the support piece  167  may be positioned to connect a side of the first electrode tab hole  163  to a second, opposite side of the first electrode tab hole  163 . Thus, the first electrode tab hole  163  may be divided into two parts by the support piece  167 .  
         [0047]     A procedure for assembling the battery constructed as above according to this embodiment of the present invention will now be described. The electrode assembly  250  may be placed into the case  200 , and the insulation case  160 , which has the support piece  167  formed thereon, may be placed on top of the electrode assembly  250 . The first and second electrode tabs  215  and  225  may be drawn from the electrode assembly  250  through the first and second electrode tab holes  163  and  165  formed in the insulation case  160 .  
         [0048]     The cap plate  110 , the insulation plate  140  and the terminal plate  150  may be successively stacked on one another in such a manner that their respective first, second, and third terminal holes  111 ,  141  and  151  are in communication with one another. The electrode terminal  130  may be inserted into the first, second, and third terminal holes  111 ,  141  and  151  by rotating it with a predetermined force, so that it extends through the cap plate  110 , the insulation plate  140  and the terminal plate  150 .  
         [0049]     The electrode terminal  130  may extend through the first terminal hole  111  of the cap plate  110  while being insulated from the cap plate  110  by the gasket  120 , so that the terminal plate  150  is electrically connected to the electrode terminal  130  while being insulated from the cap plate  110 .  
         [0050]     After being assembled in this manner, the cap assembly  100  may seal the opening  201  of the case  200 , and the first and second electrode tabs  215  and  225  may be connected to the electrode terminal  130  and the cap plate  110 , respectively.  
         [0051]     The support piece  167  of the first and/or second electrode tab holes  163  and  165  may help prevent the first and second electrode tabs  215  and  225  from being displaced in the reverse direction when subjected to external compression.  
         [0052]      FIG. 4  illustrates a top plan view of an insulation case of a battery according to another embodiment of the present invention, and  FIG. 5  illustrates a sectional view taken along line V-V of  FIG. 4 . Referring to  FIGS. 4 and 5 , a battery according to this embodiment of the present invention may be similar to the first embodiment, as described above, and may include an insulation case  260  having a reinforcement rib  269  formed along a periphery of an electrode tab hole  263 .  
         [0053]     The reinforcement rib  269  may be integral with an insulation case  260  by forming it in, e.g., an injection process, together with a rib  262  on a peripheral edge of the insulation case  260 . The reinforcement rib  269  and the rib  262  on the peripheral edge may be simultaneously formed and may protrude upwards from the upper surface of the insulation case  260  by a same height.  
         [0054]     The reinforcement rib  269  may be formed around the hole  263  and may protrude vertically from the surface of the insulation case  260 . The reinforcement rib  269  may act as support member to reduce or eliminate the possibility of the periphery of the hole  263  being deformed if an external force acts on the insulation case, particularly, on the periphery of hole  263 , in the vertical direction. In addition to helping prevent deformation of the hole  263  and the insulation case  260 , the reinforcement rib  269  may help prevent the hole  263  from widening. As a result, the upper portion of an electrode tab (not shown in  FIGS. 4 and 5 ), which may be positioned above the insulation case  260  through the hole  263 , may be supported by the insulation case  260 , which may resist deformation even when the external force acts on it from above. Accordingly, one or both electrode tab holes  263  and  265  may be prevented from being deformed and widened, which may reduce the possibility that the electrode tabs are displaced in the reverse direction via the holes  263  and  265  to short-circuit to the electrode portions of the electrode assembly.  
         [0055]     As described above, a battery according to an embodiment of the present invention may include an insulation case having an anti-deformation portion, which may help reduce or eliminate deformation when the battery is subjected to external compression. In particular, one or both of the first and second electrode tab holes, through which the first and second electrode tabs project, may be provided with a support piece crossing the opening so that, even when the battery is subjected to external compression, the first and second electrode tabs are not displaced inwardly to contact the electrode assembly, etc.  
         [0056]     Exemplary embodiments of the present invention have been disclosed 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 purpose 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. For example, it will be understood that embodiments of the present invention may be applied to one or both of the first and second electrode tab holes, and that the first and second electrode tab holes may correspond to a positive electrode tab or a negative electrode tab. Further, it will be appreciated that embodiments of the present invention may be used alone or in combination. Thus, for example, the reinforcement rib may be formed together with the support piece traversing the hole, or each may be employed individually.