Patent Publication Number: US-2015079460-A1

Title: Rechargeable battery

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Korean Patent Application No. 10-2013-0111292, filed on Sep. 16, 2013, in the Korean Intellectual Property Office, and entitled: “Rechargeable Battery,” is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     Embodiments relate generally to a rechargeable battery. 
     2. Description of the Related Art 
     A rechargeable battery is a battery that can be repeatedly charged and discharged, unlike a primary battery. A small rechargeable battery is used as a power supply for small electronic devices such as cellular phones, notebook computers, and camcorders, while a medium or large rechargeable battery is used as a power supply for driving motors in hybrid vehicles and the like. 
     A large capacity high power rechargeable battery using a non-aqueous electrolyte with high energy density has been recently developed. The large capacity high power rechargeable battery is constructed with a high power battery module having a plurality of rechargeable cells coupled to each other in series or in parallel. The high power battery module may be used in electric vehicles requiring high power. The rechargeable battery may have a cylindrical shape, a square shape, or a pouch shape. 
     SUMMARY 
     Embodiments are directed to a rechargeable battery including an electrode assembly to perform charging and discharging, an electrode terminal electrically connected to the electrode assembly, a case that receives the electrode assembly, a cap plate coupled to the case, and an insulation tape including a portion separated into at least two pieces and attached to an external surface of the case, edge portions of the case being overlapped with at least three sheets of the insulation tape attached to the external surface of the case. 
     The insulation tape may include a first tape attached to a surface of the case along a circumference of the case, a second tape attached to overlap a part of the first tape at an edge of one side of the first tape, a third tape attached to overlap a part of the first tape at an edge of another side of the first tape facing the edge of the one side of the first tape, and a fourth tape attached along the circumference of the case and covering the second tape and the third tape. 
     The second tape may overlap a part of the first tape along an edge portion of the case at a position where the cap plate of the case is located. 
     The second tape may be bent along one of the edge portions of the case. An edge of one side of the second tape may extend in a surface direction of the cap plate. An edge of another side of the second tape may extend to cover a part of the surface of the case. 
     The third tape may overlap a part of the first tape along an edge of the first tape at a bottom side of the case. 
     The third tape may be bent along another of the edge portions of the case. An edge of one side of the third tape may extend to cover a bottom side of the case. An edge of another side of the third tape may extend toward a center of the case in a length direction of the case. 
     The fourth tape may cover a same area as the first tape. 
     The fourth tape may be attached to an external side of the case to overlap an overlapped part of edges of the first tape, an edge of the second tape, and an edge of the third tape. 
     The insulation tape may overlap a corner of a bottom side of the case and a corner of the case where the cap plate is coupled to the case, with at least three sheets of the insulating tape. 
     The insulation tape may include a base tape attached along a corner at a position where the cap plate is coupled to the case and a corner at a bottom side of the case, an edge of the base tape including multiple bends such that the edge of the base tape overlaps itself with at least twice, and a cover tape covering the base tape, the cover tape being attached along a circumference of the case. 
     A bent groove may be formed in an end of the edge of the base tape. 
     The cover tape may be attached to the circumference of the case such that an edge of the cover tape is inserted into the bent groove. 
     The base tape may include a top base tape attached along a corner of the case at a position where the cap plate is coupled to the case, and a bottom base tape attached along a corner at the bottom side of the case. 
     The top base tape may be bent along a corner of the case. An edge of one side of the top base tape may be extended in a surface direction of the cap plate. An edge of another side of the top base tape may be extended to cover a part of a surface of the case. 
     The bottom base tape may be bent along a corner at a bottom side of the case. An edge of one side of the bottom base tape may extend to cover the bottom side of the case. An edge of another side of the bottom base tape may extend toward a lateral side of the case. 
    
    
     
       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 perspective view of a rechargeable battery according to an exemplary embodiment. 
         FIG. 2  illustrates a cross-sectional view with respect to a line II-II of  FIG. 1 . 
         FIG. 3  illustrates a cross-sectional view with respect to a line III-III of  FIG. 1 . 
         FIG. 4  illustrates a perspective view of a state in which a fourth tape is separated while first to third tapes are attached to a case. 
         FIG. 5  illustrates a perspective view of a state in which second to fourth tapes are separated while a first tape is attached to wrap a circumference of the case. 
         FIG. 6  illustrates a cross-sectional view of a rechargeable battery according to another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be 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. Like reference numerals refer to like elements throughout. 
       FIG. 1  illustrates a perspective view of a rechargeable battery according to an exemplary embodiment, and  FIG. 2  illustrates a cross-sectional view with respect to a line II-II of  FIG. 1 . 
     As shown in  FIG. 1  and  FIG. 2 , the rechargeable battery  100  may include an electrode assembly  10  to perform charging and discharging, terminals  22  and  24  electrically connected to the electrode assembly  10 , a case  30  that receives the electrode assembly  10  while the terminals  22  and  24  are drawn out of the case, and an insulation tape  40  attached to an external surface of the case  30 . A cap plate  21  may be installed in an opening  31  of the case  30 , and the terminals  22  and  24  including a positive electrode terminal  22  and a negative terminal  24  may be installed on the cap plate  21 . 
     A positive electrode  11  and a negative electrode  12  each include a coated region that is generated by coating an active material on a current collector made of a thin-plate metal foil, and respective uncoated regions  11   a  and  12   a  on which the active material is not coated. The positive electrode uncoated region  11   a  may be formed at a first end in a length direction of the positive electrode  11 , and the negative uncoated region  12   a  may be formed at a second end in a length direction of the negative electrode  12 . 
     The positive electrode  11  and the negative electrode  12  may be stacked with a separator  13  that is an insulator therebetween, may be spirally-wound by using a spirally wound roll, and may form a jellyroll-type electrode roll  10 . The electrode roll  10  may be pressurized by a press and may be formed to be flat so that the electrode roll  10  may be installed in the case  30 . 
     The case  30  may be substantially formed to be a cuboid, and the opening  31  may be formed in one side thereof. 
     The cap plate  21  may be formed as a thin plate and may be coupled to and installed at the opening  31  of the case  30 . A seal stopper  25  may be installed in an electrolyte injection opening  23  in the cap plate  21 . A vent plate  29  in which a notch  29   a  is formed may be installed in a vent hole  27  in the cap plate  21  so as be opened at a predetermined pressure. 
     The positive electrode terminal  22  and the negative electrode terminal  24  may be installed to pass through the cap plate  21 . Flanges  22   a  and  24   a  supported below the cap plate  21  may be formed at the bottom of the positive electrode terminal  22  and the negative electrode terminal  24 . An external circumferential surface of an upper column of the positive electrode terminal  22  and the negative electrode terminal  24  that protrudes outside the cap plate  21  may be screw-processed. In addition, nuts  26  supporting the positive electrode terminal  22  and the negative electrode terminal  24  at their tops may be fastened to the positive electrode terminal  22  and the negative electrode terminal  24 . 
     A gasket  28   a  may be installed between the positive electrode terminal  22  and the cap plate  21 . Further, a gasket  28   b  may be installed between the negative terminal  24  and the cap plate  21  to seal a space between the terminals  22  and  24  and the cap plate  21 . 
     The positive electrode terminal  22  may be electrically connected to the positive electrode  11  through a positive electrode lead tab  22   b  as a medium, and the negative terminal  24  may be electrically connected to the negative electrode  12  through a negative electrode lead tab  24   b  as a medium. An insulation member  28   c  may be inserted between the positive electrode terminal  22  and the positive electrode lead tab  22   b  and between the negative terminal  24  and the negative electrode lead tab  24   b.    
     The insulation tape  40  may be attached to an external surface of the case  30 . 
       FIG. 3  illustrates a cross-sectional view with respect to a line of  FIG. 1 ,  FIG. 4  illustrates a perspective view of a state in which a fourth tape is separated while first to third tapes are attached to a case, and  FIG. 5  illustrates a perspective view of a state in which second to fourth tapes are separated while a first tape is attached to wrap a circumference of the case. 
     As shown in  FIG. 3  to  FIG. 5 , the insulation tape  40  may be attached as at least two divided parts to the external surface of the case  30 . The insulation tape  40  may include a first tape  41  attached along a circumference of the case  30 , a second tape  42  attached to a side at which the terminals  22  and  24  protrude from the case  30 , a third tape  43  attached to a bottom side  33  of the case  30 , and a fourth tape  44  that covers the second tape  42  and the third tape  43 . 
     The first tape  41  may be attached to insulate the external surface of the case  30  in a first manner. The first tape  41  may be attached along the circumference of the case  30  between a part at which the terminals  22  and  24  protrude from the case  30  and the bottom side  33  of the case  30 . By the attachment of the first tape  41 , the cap plate  21  and the external surface of the bottom side  33  of the case  30  may not be insulated but may be exposed. The second tape  42  may be attached to the first tape  41  while the second tape  42  may partially overlap the first tape  41 . 
     The second tape  42  may be attached to overlap the first tape  41  at a corner of one side of the case  30 . A center portion of the second tape  42  in a length direction may be bent and attached along the corner of the one side of the case  30 . An edge of one side of the second tape  42  may extend in a surface direction of the cap plate  21 , and an edge of another side of the second tape  42  may extend to cover the surface of the case  30 . The second tape  42  may be attached to partially cover the cap plate  21  and the case  30  and thus may be attached to insulate the corner of the case  30  at the part where the cap plate  21  is installed. 
     When the case  30  is formed as a rectangle, multiple second tapes  42  may be attached to the position where the cap plate  21  is installed while varying an attached length. For example, the second tape  42  may be attached such that a part of the second tape  42  that is attached to the corner that corresponds to a long side of the case  30  may be longer than a part of the second tape  42  that is attached to a corner that corresponds to a short side of the case  30 . The second tape  42  may be attached to an external side of the first tape  41  such that the second tape  42  may partially overlap the external side of the first tape  41 , thereby further insulating the corner of the case  30  at the position where the cap plate  21  is installed. 
     The third tape  43  may be attached to overlap the first tape  41  at the corner of the bottom side of the case  30 . In detail, a center portion of the third tape  43  in the length direction may be bent and attached along the corner of the bottom side of the case  30 . An edge of one side of the second tape  42  may extend in the surface direction of the cap plate  21 . An edge of another side of the second tape  42  may extend to partially cover the bottom side of the case  30 . The third tape  43  may be attached to insulate the corner of the case  30  at the bottom side position. The third tape  43  may include the same material as the first tape  41  and the second tape  42 . 
     The fourth tape  44  covers the entire area of the first tape  41 , the second tape  42 , and the third tape  43  with the same area as the first tape  41 . The fourth tape  41  may be attached along the circumference of the case  30 . While the first tape  41 , the second tape  42 , and the third tape  43  may insulate a part of the case  30  with double layers, the fourth tape  44  may be attached to cover the first tape  41 , the second tape  42 , and the third tape  43  to partially insulate the case  30  with three layers. The fourth tape  44  allows multiple insulation performance at the separated parts of the edge of the first tape  41 , the second tape  42 , and the third tape  43  to thus prevent permeation of a foreign material such as moisture into the case  30  and prevent generation of damage to the rechargeable battery  100  caused by the foreign material. 
     The insulation tape  40  may be attached at the edge of the case  30  while overlapping the case  30  with at least three sheets, such that external moisture may not pass through the insulation tape  40  to be provided into the case  30 . Accordingly, generation of a short circuit and corrosion of the rechargeable battery  100  may be prevented, and durability and stability of the rechargeable battery may be improved. 
       FIG. 6  illustrates a cross-sectional view of a rechargeable battery according to another exemplary embodiment. The same reference numerals used in  FIG. 1  to  FIG. 5  indicate the same members with the same functions in  FIG. 6 . A detailed description with regard to features indicated by the same reference numerals will not be repeated. 
     As shown in  FIG. 6 , an insulation tape  140  of a rechargeable battery  200  according to this exemplary embodiment may include a base tape  141  attached to an external surface of a case  30 , and a cover tape  143  that covers the base tape  141 . The base tape  141  may include a top base tape  141   a  attached to cover an edge of a top where the cap plate  21  of the case  30  is installed, and a bottom base tape  141   b  attached to cover an edge on a bottom side of the case  30 . 
     At least two top base tapes  141   a  may be attached to the top of the case  30  and may insulate the top of the case  30 . One side of the top base tape  141   a  may be extended to cover a part of the cap plate  21  and another side thereof may extend to cover a part of the case  30 . A bent groove  141   c  overlapping with at least two sheets may be formed at an edge connected to the cover tape  143  in the top tape  141   a . As described, the edge of the top base tape  141   a  may overlap with at least two sheets in order to prevent permeation of a foreign material such as moisture into the case  30 . 
     The bottom base tape  141   b  may be attached to insulate the bottom side of the case  30 . The bottom base tape  141   b  may be bent along the edge of the bottom side of the case  30 . One side of the bottom base tape  141   b  may extend in a lateral direction of the case  30 , and another side of the bottom base tape  141   b  may be formed to cover the bottom side of the case  30 . The bent groove  141   c  that is bent to overlap with at least two sheets may be formed at the part of the bottom base tape  141   b  that is connected to the cover tape  143 , for example, an edge of the bottom base tape  141   b  extending in the lateral direction of the case  30 . The edge of the bottom base tape  141   b  may overlap with at least two sheets. Accordingly, permeation of a foreign material such as moisture into the case  30  may be prevented. 
     The cover tape  143  may be attached to the external surface of the case  30 . Respective sides of the edge of the cover tape  143  may be inserted into the bent groove  141   c  of the top base tape  141   a  and the bent groove  141   c  of the bottom base tape  141   b . The cover tape  143  may be attached to cover the top tape  141   a  and the bottom tape  141   b  while being inserted into the bent grooves  141   c  of the top tape  141   a  and the bottom tape  141   b , thereby preventing permeation of a foreign material such as moisture into the case  30  and further improving durability of the rechargeable battery  100 . 
     By way of summation and review, a square rechargeable battery includes an electrode group (i.e., an electrode assembly) including an anode and a cathode positioned with a separator interposed therebetween, a case with a space for housing the electrode group, and a cap plate for sealing the case and having a terminal hole into which an electrode terminal is inserted, the electrode terminal being electrically connected with the electrode group and inserted into the terminal hole so as to be outwardly protruded from the case. 
     An insulation tape is attached to an external part of the rechargeable battery to prevent a foreign material such as moisture from being permeated into the case. However, the insulation tape is generally attached to a circumference of the rechargeable battery as a single insulation tape. Therefore, foreign materials such as moisture may be easily permeate into the case at a boundary of the case and the insulation tape. The durability of the insulating tape may be worsened by corrosion of the rechargeable battery. 
     Embodiments provide a rechargeable battery in which permeation of a foreign material such as moisture is prevented by attaching at least two sheets of insulation tape to an external surface of a case. Thereby, durability of the rechargeable battery may be improved. 
     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 ordinary 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 thereof as set forth in the following claims.