Abstract:
A rechargeable battery includes an electrode assembly and a cap plate. The electrode assembly is located in a case of the battery, and the cap plate a cap plate is over an opening of the case. The battery also includes a terminal and a gasket. The terminal includes a plurality of sealing protrusions. The gasket is located between the terminal and cap plate and contacts the plurality of sealing protrusions. Together, the sealing protrusions and gasket establish a barrier which prevents electrolyte solution in the case from reaching and eroding the terminal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Korean Patent Application No. 10-2013-0109961, filed on Sep. 12, 2013, and entitled, “Rechargeable Battery,” is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     One or more embodiments described herein relate to a battery. 
     2. Description of the Related Art 
     Unlike a primary battery, a rechargeable battery can be repeatedly charged and discharged. Low-capacity rechargeable batteries output low levels of power, and therefore are used in small portable electronic devices such as mobile phones, laptop computers, and camcorders. High-capacity rechargeable batteries are formed by coupling multiple rechargeable batteries in series to output high levels of power. These batteries are suitable for use in driving motors of electric vehicles. Also, rechargeable batteries may be formed to have a cylindrical or prismatic shape. 
     In order for a rechargeable battery to properly operate, a sufficient amount of electrolyte solution may be injected into the battery case for purposes of impregnating an electrode assembly therein. These batteries have also been equipped with a gasket and lower insulating member. The gasket is provided between a terminal and cap plate to prevent the electrolyte solution from contacting a terminal of the rechargeable battery. The lower insulating member is provided between the cap plate and a current collector. 
     When charging and discharging is continuously repeated, operating performance of the gasket and/or lower insulating member may deteriorate over time as a result of an increase in internal battery temperature or pressure. This deterioration may allow the electrolyte solution in the case to permeate between the gasket and one or more battery terminals, or between the lower insulating member and battery terminals. As a result, the terminals may erode by the electrolyte solution and short circuit may occur inside the battery. Also, a current path may form between the terminal and cap plate. 
     The gasket is to be compressed between the terminal and cap plate. Accordingly, the gasket has been made of a material having elasticity and rigidity. The lower insulating member is made of a material with less elasticity and less rigidity. These differences in materials may increase the cost of implementing the gasket and lower insulating member in the battery. 
     Attempts have been made to overcome these drawbacks. For example, the gasket and lower insulating member may be integrally formed to prevent terminal erosion or internal short-circuits caused by the electrolyte solution. This will allow the lower insulating material and gasket to be made of the same material. However, integrally forming the gasket and lower insulating also increases manufacturing costs because of the special design required for the integral formation. 
     SUMMARY 
     In accordance with one embodiment, a rechargeable battery includes a case; an electrode assembly in the case; a cap plate over an opening of the case; a first terminal in the cap plate and including a plurality of sealing protrusions; and a first gasket between the first terminal and cap plate and contacting the plurality of sealing protrusions. The first terminal may include a first terminal flange protruding from a first pillar terminal. The sealing protrusions may be on the first terminal flange. 
     Each of the sealing protrusions has a closed-curved line shape, and the closed-curved line shape is around an external circumferential surface of the first pillar terminal. The first gasket may include a compression protrusion between the sealing protrusions. The compression protrusion may be in a closed-curved line shape. 
     The plurality of sealing protrusions may include a second sealing protrusion spaced from a first sealing protrusion, and the compression protrusion may be between the first and second sealing protrusions. The compression protrusion may include a second compression protrusion spaced from a first compression protrusion. 
     The plurality of sealing protrusions may include a first sealing protrusion, a second sealing protrusion spaced from the first sealing protrusion, and a third sealing protrusion spaced from the second sealing protrusion. The first compression protrusion may be between the first and second sealing protrusions. The second compression protrusion may be between the second and third sealing protrusions. 
     The rechargeable battery may include a first lower insulating member between the cap plate and electrode assembly, wherein the first lower insulating member is connected to the first terminal. The first gasket and the first lower insulating member may be made of different materials. The first gasket may be made of a material including perfluoroalkoxy, and the lower insulating member may be made of a material including polypropylene. 
     In accordance with another embodiment, a rechargeable battery includes a terminal; a gasket coupled to the terminal; and at least one surface between the gasket and a surface of the terminal, wherein the at least one surface and the surface of the terminal have different shapes, and wherein the at least one surface and the gasket establish a barrier between an interior space of the battery which includes an electrolyte solution and the terminal. 
     The shape of the surface of the terminal may be substantially flat, and the shape of the at least one surface may be curved. The at least one curved surface may be between the surface of the terminal and the gasket. The at least one curved surface may have a convex shape, and/or may be integrally formed with the terminal. 
     A plurality of surfaces between the gasket and the surface of the terminal may establish barriers between the interior space of the battery and the terminal. The plurality of surfaces may be concentrically formed around the terminal. The plurality of surfaces are integrally formed with the terminal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features will become apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which: 
         FIG. 1  illustrates a first embodiment of a rechargeable battery; 
         FIG. 2  illustrates a view along section line II-II in  FIG. 1 ; 
         FIG. 3  illustrates an exploded view of the rechargeable battery; 
         FIG. 4  illustrates a partial cross-sectional view of the rechargeable battery; 
         FIG. 5  illustrates a second embodiment of a rechargeable battery; 
         FIG. 6  illustrates a partial exploded view of the battery in  FIG. 5 ; 
         FIG. 7  illustrates a partial cross-sectional view of the battery in  FIG. 5 ; 
         FIG. 8  illustrates a third embodiment of a rechargeable battery; 
         FIG. 9  illustrates a partial exploded view of the battery in  FIG. 8 ; and 
         FIG. 10  illustrates a partial cross-sectional view of the battery in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments are described more fully hereinafter with reference to the accompanying drawings; however, they may 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 exemplary implementations to those skilled in the art. 
     In the drawing 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. 
       FIG. 1  illustrates a first embodiment of a rechargeable battery  100 , and  FIG. 2  illustrates a cross-sectional view along line II-II in  FIG. 1 . Referring to  FIGS. 1 and 2 , rechargeable battery  100  includes an electrode assembly  10 , first and second terminal sections  30  and  40 , and a cap plate  20 . The electrode assembly in a case  26  and may be formed by winding a first electrode  11  and a second electrode  12 . A separator  13  may be interposed between electrodes  11  and  12 . The first and second terminal sections  30  and  40  are electrically combined with electrode assembly  10 . The cap plate  20  is connected over an opening in the case  26 . First and second lower insulating members  60  and  80  are also provided in the case  26 . 
     The rechargeable battery  100  is illustrated to have a prism-shaped lithium ion rechargeable battery. However, in other embodiments, battery  100  may have a different shape and/or may be of a type different from a lithium polymer battery. 
     The first electrode  11  may be a negative electrode and the second electrode  12  may be a positive electrode. In other embodiments, the first electrode  11  may be a positive electrode and the second electrode  12  may be a negative electrode. 
     The electrode assembly  10  may have a jelly roll shape by winding the first electrode  11 , the second electrode  12 , and the separator  13  together. The first electrode  11  and the second electrode  12  may respectively include a current collector formed of a thin metal foil and an active material coated on the surface of each current collector. 
     The first electrode  11  and the second electrode  12  may be divided into coated regions and uncoated regions. The coated regions may correspond to locations where an active material is coated on the current collector. First and second electrode uncoated regions  11   a  and  12   a  correspond to locations where the active material is not coated. 
     Additionally, the coated regions may occupy a greater part of the first and second electrodes  11  and  12  in the electrode assembly  10 . The first and second electrode uncoated regions  11   a  and  12   a  may be disposed at respective sides of the coated regions and may have a jelly roll shape. In alternative embodiments, the electrode assembly  10  may have a layered structure, where, for example, the first and second electrodes  11  and  12 , respectively formed of a plurality of sheets, are layered with one or more separators  13  interposed between them. 
     The first terminal section  30  may be electrically connected to the first electrode uncoated region  11   a  through a first current collecting member  50 . The second terminal section  40  may be electrically connected to the second electrode uncoated region  12   a  through a second current collecting member  70 . 
     The case  26  may be roughly formed in a cuboid shape and may include an opening formed at one side thereof. In other embodiments, the case may have a different shape such as, for example, a cylinder or a pouch. 
     The cap plate  20  may be made of a thin plate and may close and seal the opening while being combined thereto. In addition, the cap plate  20  may be formed with an electrolyte injection opening  21  for injecting an electrolyte solution into the sealed case  26 . The electrolyte injection opening  21  may be closed and sealed by a sealing cap  22  after injection. 
     A vent hole  23  may be provided in cap plate  20 . A vent plate  24  may be provided in the vent hole  23  and broken when internal pressure of the sealed case  26  is increased above a predetermined value. 
     The first and second terminal sections  30  and  40  may respectively include first and second terminals  31  and  41 , first and second terminal plates  32  and  42 , first and second terminal insulating members  33  and  43  between the first and second terminal plates  32  and  42  and the cap plate  20 , and first and second gaskets  34  and  44 . 
     The first terminal  31  may be formed in a rivet shape and may include a first pillar terminal  31   a , a first terminal flange  31   b  protruding from the first pillar terminal  31   a , and a first terminal coupling protrusion  31   c  protruding from the first terminal flange  31   b . The second terminal  41  may have a structure similar to the first terminal  31 . 
     The first current collecting member  50  includes a first electrode coupling portion  51  connected to the first electrode  11 , a first terminal coupling portion  52  connected to the first electrode coupling protrusion  31   c  of the first electrode  41 , and a fuse portion  53  including a fuse hole in the first electrode coupling portion  52 . The second current collecting member  70  may have a structure similar to the current collecting member  50 . 
     The first and second lower insulating members  60  and  80  may be disposed close to the cap plate  20  inside the case  26 . In one embodiment, the first terminal section  30 , first current collecting member  50 , and first lower insulating member  60  have structures similar to the second terminal section  40 , second current collecting member  70 , and second lower insulating member  80 , respectively. As previously indicated, the first terminal  31  may have a rivet shape. In alternative embodiments, the first terminal  31  may have a different shape such as a bolt or plate shape. 
       FIG. 3  illustrates a partial exploded view of the rechargeable battery  100 , and  FIG. 4  illustrates a partial cross-sectional view of this battery. Referring to  FIG. 3  and  FIG. 4 , first terminal  31  may be formed to have a plurality of sealing protrusions. The sealing protrusions in the first terminal  31  may be formed to have a closed-curved line shape, to enclose a periphery of the external circumferential surface of the first pillar terminal  31   a . In one embodiment, the sealing protrusions are formed at a first terminal flange  31   b  of the first terminal  31 . In other embodiments, the sealing protrusions may be formed on the first terminal flange  31   b  and/or may be formed on the external circumference of the first pillar terminal  31   a.    
     The first gasket  34  includes a first gasket body  34   a , a first gasket flange  34   b  protruding from the gasket body  34   a , and a first through-hole  34   c  which the first pillar terminal  31   a  penetrates. The first through-hole  34   c  in the first gasket  34  is placed on and combined with the first pillar terminal  31   a  of first terminal  31 . In this arrangement, first gasket flange  34   b  is on or closely attached to first terminal flange  31   b.    
     In addition, in their combined form, the first gasket  34  and first terminal  31  are inserted in a first coupling hole  61  of the first lower insulating member  60 . The first terminal flange  31   b  is fixed to a second coupling hole or recess  62  of the first lower insulating member  60 . The first lower insulating member  60  is combined with the cap plate  20  by a fixing protrusion  63 , such that the first terminal  31  and first gasket  34  are fixed to the cap plate  20  through the lower insulating member  60 . 
     The first terminal coupling portion  52  of the first current collecting member  50  is combined to the first coupling protrusion  31   c  of the first terminal  31 . The first terminal coupling portion  52  is then fixed to the first coupling hole  62 . 
     In one embodiment, a plurality of sealing protrusions  31   d  may be formed at one side of the first terminal flange  31   b  facing the first gasket flange  34   b . The sealing protrusions  31   d  may be integrally formed with the first terminal flange  31   b , or the sealing protrusions  31   d  and the first terminal flange  31   b  may have mating features which allow them to be coupled to one another. In other embodiments, the sealing protrusions  31   d  may be integrally formed or coupled to another portion of first pillar terminal  31   a , including but not limited to a vertical surface of this terminal. 
     The sealing protrusions  31   d  may include a first sealing protrusion  31   d   1  and a second sealing protrusion  31   d   2 . The first sealing protrusion  31   d   1  is spaced from an external circumferential surface of the first pillar terminal  31   a . The first sealing protrusion  31   d   1  may have a closed-curved line shape to enclose a periphery of the external circumferential surface of the first pillar terminal  31   a . The second sealing protrusion  31   d   2  is spaced from the first sealing protrusion  31   d   1 , and may have a closed-curved line shape to enclose the first sealing protrusion  31   d   1 . The first sealing protrusion  31   d   1  is disposed between the second sealing protrusion  31   d   1  and the first pillar terminal  31   a . In an alternative embodiment, the first and second sealing protrusions  31   d   1  and  31   d   2  may have a shape different from a closed-curved line shape. 
     The first and second sealing protrusions  31   d   1  and  31   d   2  may be respectively formed with a plurality of protrusions disposed apart from each other. 
     The first gasket body  34   a  of the first gasket  34  is disposed between the first terminal  31  and cap plate  20 . The first gasket flange  34   b  is disposed between the first terminal flange  31   b  and the first lower insulating member  60 . 
     In one embodiment, the first terminal flange  31   b  is closely attached to the first gasket flange  34   b  and may be formed with the first and second sealing protrusions  31   d   1  and  31   d   2 , to thereby increase the contact area of the first gasket flange  34   b  and the first terminal flange  31   b . As a result, a passage for the electrolyte solution cannot be easily established or may be prevented between the first gasket flange  34   b  and the first terminal flange  31   b.    
     Moreover, because the formation of such a passage is prevented, a short circuit caused by a current path between the first terminal  31  and cap plate  26 , formed by the electrolyte solution passing between the first terminal  31  and the first gasket  34 , may be prevented. 
     In one embodiment, the first gasket  34  and first lower insulating member  60  is not integrally formed. As a result, the first gasket  34  and first lower insulating member  60  may be made of different materials. For example, the first gasket  34  may be made of perfluoroalkoxy and first lower insulating member  60  may be made of polypropylene. This embodiment may be less expensive to manufacture because the polypropylene used to form the first lower insulating member  60  may be cheaper to use than the perfluoroalkoxy used to form the first gasket  34 . 
     In another embodiment, the first gasket  34  and lower insulating member  60  may be integrally formed. In this embodiment, the first gasket  34  may have elastic and rigid features. Because the first lower insulating member  60  is made of the same material as the first gasket  34  (e.g., perfluoroalkoxy), the first lower insulating member will also have elastic and rigid features. 
     In embodiments where the first gasket  34  and first lower insulating member  60  are separated manufactured (e.g., not integrally formed), an increase in the cost of manufacturing rechargeable battery  100  can be avoided, because the first lower insulating member  60  can be made of a cheaper material than the first gasket  34 . 
       FIG. 5  and  FIG. 6  illustrate a second embodiment of a rechargeable battery  200 , and  FIG. 7  illustrates a partial cross-sectional view of this battery. Referring to  FIGS. 5 to 7 , the rechargeable battery  200  may have the same structure as battery  100 , except for first gasket  234 . 
     The first gasket  234  includes a first gasket body  234   a , a first gasket flange  234   b , a first through-hole  234   c , and a compression protrusion  234   d . The compression protrusion  234   d  may be formed in a closed-curved line shape, and may be disposed at one side of the first gasket flange  234   b  facing the first terminal flange  31   b  of the first terminal  31 . In an alternative embodiment, the compression protrusion  234   d  may be formed in the first gasket flange  234   b , and may be formed at the external circumferential side of the first gasket body  234   a.    
     Also, in the present embodiment, the first terminal flange  31   b  of the first terminal  31  is formed with the sealing protrusion  31   d  including the first sealing protrusion  31   d   1  and the second sealing protrusion  31   d   2 . 
     When the first through-hole  234   c  in the first gasket  234  is inserted on and combined with by the pillar terminal  31   a  of the first terminal  31 , the compression protrusion  234   d  is disposed and pressed between the first sealing protrusion  31   d   1  and the second sealing protrusion  31   d   2 . 
     Because the first terminal flange  31   b  is closely attached to the first gasket flange  234   b  and is formed with the first and second sealing protrusions  31   d   1  and  31   d   2 , and because the compression protrusion  234   d  is provided between the first and second sealing protrusions  31   d   1  and  31   d   2 , the contacting area between the first gasket flange  234   b  and the first terminal flange  31   b  may be increased. As a result, the space between the first and second sealing protrusions  31   d   1  and  31   d   2  is filled by the compression protrusion  234   d.    
     Thus, a passage for the electrolyte solution between the first gasket flange  234   b  and the first terminal flange  31   b  cannot be easily established or may be prevented. Because such a passage may be prevented, a short circuit caused by a current path formed between the first terminal  31  and the cap plate  26 , as a result of the electrolyte solution passing between the first terminal  31  and the first gasket  234 , may be prevented. 
       FIG. 8  and  FIG. 9  illustrate a third embodiment of a rechargeable battery  300 , and  FIG. 10  illustrates a partial cross-sectional view of this battery. Referring to  FIGS. 8-10 , rechargeable battery  300  may have the same structure as the aforementioned embodiments, except for a first terminal  331  and a first gasket  334 . 
     In this embodiment, the first terminal  331  is formed in a rivet shape and includes a first pillar terminal  331   a , a first terminal flange  331   b  protruding from the first pillar terminal  331   a , and a first terminal coupling protrusion  331   c  protruding from the first terminal flange  331   b . In an alternative embodiment, first terminal  331  may have a different shape such as a bolt or plate shape. 
     In addition, the first terminal  331  includes a plurality of sealing protrusions  331   d  including a first sealing protrusion  331   d   1 , a second sealing protrusion  331   d   2  spaced from the first sealing protrusion  331   d   1 , and a third sealing protrusion  331   d   3  spaced from the second sealing protrusion  331   d   2 . The second sealing protrusion  331   d   2  may be between the first sealing protrusion  331   d   1  and the third sealing protrusion  331   d   3 . 
     The first sealing protrusion  331   d   1 , second sealing protrusion  331   d   2 , and third sealing protrusion  331   d   3  are respectively formed in a closed-curved line shape to enclose a periphery of an external circumferential surface of the first pillar terminal  31   a . These protrusions may also be formed on the first terminal flange  331   b . In an alternative embodiment, the first sealing protrusion  331   d   1 , second sealing protrusion  331   d   2 , and third sealing protrusion  331   d   3  may be formed on an external circumferential surface in the first pillar column  331   a.    
     The first gasket  334  a first gasket body  334   a , a first gasket flange  334   b  protruding from the first gasket body  334   a , a first through-hole  334   c  through which the first pillar terminal  331   a  passes, and a compression protrusion  334   d . More specifically, compression protrusion  334   d  may be formed in a closed-curved line shape and may be disposed at one side of the first gasket flange  334   b  facing the first terminal flange  331   b  of the first terminal  331 . In an alternative embodiment, compression protrusion  334   d  may be formed at an external circumferential surface of the first gasket body  334   a.    
     The compression protrusion  334   d  includes a first compression protrusion  334   d   1  formed in a closed-curved line shape, and a second compression protrusion  334   d   2  in a closed-curved line shape and spaced from the first compression protrusion  334   d   2 . 
     In one embodiment, when the first pillar terminal  331   a  of the first terminal  331  is inserted into the first through-hole  334   c  of the first gasket  334  (to allow the first gasket flanges  334   b  to be closely attached to the first terminal flange  331   b ), the first compression protrusion  334   d   1  is pressed while being disposed between the first and second sealing protrusions  331   d   1  and  331   d   2 . Also, the second compression protrusion  334   d   2  is pressed while being disposed between the second and third sealing protrusions  331   d   2  and  331   d   3 . 
     The first terminal flange  331   b  is closely attached to the first gasket flange  334   b  and is formed with the first sealing protrusion  331   d   1 , second sealing protrusion  331   d   2 , and third sealing protrusion  331   d   3 . The first compression protrusion  334   d   1  is formed between the first and second sealing protrusions  331   d   2  and  331   d   3 . Also, the second compression protrusion  334   d   2  is formed between the second and third sealing protrusions  331   d   2  and  331   d   3 . This arrangement may increase the contacting area of the first gasket flange  334   b  and the first terminal flange  331   b.    
     In addition, the space between the first and second sealing protrusions  331   d   1  and  331   d   2  and the space between the second and third sealing protrusions  331   d   2  and  331   d   3  are respectively filled by the first and second compression protrusions  334   d   1  and  334   d   2 . Thus, a passage for the electrolyte solution between the first gasket flange  334   b  and the first terminal flange  331   b  cannot be easily established or may be prevented. 
     Because this passage cannot be easily established or prevented, a short circuit caused by a current path formed between the first terminal  331  and the cap plate  26 , as a result of the electrolyte solution passing between the first terminal  331  and the first gasket  334 , may be prevented. 
     In accordance with one or more of the aforementioned embodiments, a rechargeable battery has a terminal structure that prevents permeation of an electrolyte solution between a terminal and a cap plate. In accordance with these or other embodiments, a rechargeable battery is provided to have lower manufacturing costs. While the aforementioned embodiments have been described as corresponding to a rechargeable battery, other embodiments may apply to other types of batteries. 
     Example embodiments 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. In some instances, as would be apparent to one of skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of 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.