Abstract:
A rechargeable battery and a battery module. A rechargeable battery includes: a unit cell including an electrode assembly, a case containing the electrode assembly, a cap plate covering an opening of the case, and a terminal electrically connected to the electrode assembly and protruding through the cap plate; and a cover including an electrically insulating material and covering the cap plate, the cover having an opening exposing the terminal therethrough.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Application No. 61/662,142, filed on Jun. 20, 2012 in the United States Patent &amp; Trademark Office, the entire content of which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    Aspects of embodiments of the present invention relate to a rechargeable battery and a module thereof. 
         [0004]    2. Description of the Related Art 
         [0005]    Unlike a primary battery that is not rechargeable, a rechargeable battery may be repeatedly charged and discharged. A small-capacity rechargeable battery is typically used for small portable electronic devices, such as mobile phones, notebook computers, camcorders, and the like, while a large-capacity rechargeable battery may be used as a motor-driving power source for a hybrid vehicles, or an electric vehicle for example. 
         [0006]    The rechargeable battery may be used in small electronic devices as a single-cell battery or as a motor-driving power source, for example, as a battery module in which a plurality of cells are electrically connected. The rechargeable battery module may be formed by connecting electrode terminals through a bus bar. 
         [0007]    In the rechargeable battery module, neighboring unit cells are electrically connected, and an insulating layer may be formed for external insulation of each unit cell. However, portions where the insulating layer is not provided may be electrically connected through water. That is, an aqueous circuit may cause an external short circuit of the unit cell. 
         [0008]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY 
       [0009]    According to an aspect of embodiments of the present invention, a rechargeable battery and a module thereof are configured for preventing or substantially preventing an external short circuit caused by an aqueous circuit. According to another aspect of embodiments of the present invention, a rechargeable battery and a module thereof have improved external insulation properties. 
         [0010]    According to an exemplary embodiment of the present invention, a rechargeable battery includes: a unit cell including an electrode assembly, a case containing the electrode assembly, a cap plate covering an opening of the case, and a terminal electrically connected to the electrode assembly and protruding through the cap plate; and a cover including an electrically insulating material and covering the cap plate, the cover having an opening exposing the terminal therethrough. 
         [0011]    The rechargeable battery may further include an insulation member receiving the unit cell, and the cover may cover the insulation member. 
         [0012]    The insulation member may include an edge portion and an opening in the edge portion, and the edge portion may partially cover a first surface of the unit cell. The insulation member may be expandable to receive the unit cell through the opening in the edge portion. The rechargeable battery may further include a cell seal between the edge portion and the cover. 
         [0013]    At least one of the edge portion or the cover may be attached to the unit cell via an adhesive, 
         [0014]    The cover may be coupled to a portion of the unit cell. 
         [0015]    The rechargeable battery may further include a cell seal between the cap plate and the cover. 
         [0016]    The rechargeable battery may further include a terminal seal surrounding the terminal and being arranged between the cover and the cap plate. 
         [0017]    The terminal may include a first terminal and a second terminal, the unit cell may further include an insulator between the cap plate and the first terminal, and a connection plate between the cap plate and the second terminal, and the opening of the cover may include a first opening exposing the first terminal and connected with the insulator, and a second opening exposing the second terminal and connected with the connection plate. 
         [0018]    The cover may have a drain groove extending to a side of the cover. 
         [0019]    The cover may include a first portion extending from a surface of the cover toward the unit cell, the first portion being coupled to the unit cell. 
         [0020]    According to another exemplary embodiment of the present invention, a battery module includes: a plurality of unit cells, each including an electrode assembly, a case containing the electrode assembly, a cap plate covering an opening of the case, and a terminal electrically connected to the electrode assembly and protruding through the cap plate; and a cover including an electrically insulating material and covering the unit cells, the cover having at least one opening exposing the terminals therethrough. 
         [0021]    The battery module may further include an insulation member receiving the unit cells, and the cover may cover the insulation member. 
         [0022]    The insulation member may include an integral insulation member including a cell barrier separating adjacent unit cells of the plurality of unit cells. 
         [0023]    The battery module may further include a plurality of cell seals between the insulation member and the cover, each of the cell seals being arranged around a periphery of a first surface of a corresponding unit cell of the plurality of unit cells. 
         [0024]    The cover may include an integral cover member covering the plurality of unit cells. 
         [0025]    The battery module may further include a plurality of terminal seals, each surrounding the terminal of a corresponding unit cell of the plurality of unit cells and being arranged between the cover and the cap plate of the corresponding unit cell. The battery module may further include a plurality of cell seals, each between the cover and the cap plate of a respective unit cell of the corresponding unit cells, each of the cell seals being arranged around a periphery of the cap plate of the respective unit cell and surrounding the terminal of the respective unit cell. 
         [0026]    The cover may have a drain groove extending to a side of the cover, 
         [0027]    A rechargeable battery module according to an exemplary embodiment includes unit cells each forming rechargeable battery, an insulation member for receiving the unit cells, and a cover for covering the unit cells. 
         [0028]    A rechargeable battery according to an exemplary embodiment includes an electrode assembly for charging and discharging currents, a case for containing the electrode assembly, a cap plate connected with an opening of the case, an electrode terminal attached to a terminal hole of the cap plate, an insulation member for receiving the case, and a cover for covering the cap plate. 
         [0029]    According to an exemplary embodiment, the unit cell can be received by the insulation member and covered with the cover, thus preventing or substantially preventing an external short circuit caused by an aqueous circuit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The accompanying drawings, together with the specification, illustrate some exemplary embodiments of the present invention, and, together with the description, serve to explain principles and aspects of the present invention. 
           [0031]      FIG. 1  is a perspective view of a rechargeable battery module according to an exemplary embodiment of the present invention. 
           [0032]      FIG. 2  is an exploded perspective view of the rechargeable battery module of  FIG. 1 . 
           [0033]      FIG. 3  is an exploded perspective view of a rechargeable battery according to an exemplary embodiment of the present invention. 
           [0034]      FIG. 4  is a cross-sectional view of the rechargeable battery of  FIG. 3 , taken along the line IV-IV. 
           [0035]      FIG. 5  is a cross-sectional view of the rechargeable battery module of  FIG. 1 , taken along the line V-V. 
           [0036]      FIG. 6  is an exploded perspective view of a rechargeable battery according to another exemplary embodiment of the present invention. 
           [0037]      FIG. 7  is an exploded perspective view of a rechargeable battery according to another exemplary embodiment of the present invention. 
           [0038]      FIG. 8  is an exploded perspective view of a rechargeable battery module according to another exemplary embodiment of the present invention. 
           [0000]    
         
           
                 
               
                 
                 
               
                 
               
                 
                 
               
                 
               
                 
                 
               
             
                 
                     
                 
                 
                   Description of Reference Numerals Indicating 
                 
                 
                   Some Elements In the Drawings 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                   10: electrode assembly 
                   11: first electrode 
                 
                 
                   11a, 12a: coated region 
                   11b, 12b: uncoated region 
                 
                 
                   12: second electrode 
                   13: separator 
                 
                 
                   15: case 
                   20: cap plate 
                 
                 
                   21: first electrode terminal 
                   21a, 22a: rivet terminal 
                 
                 
                   21b, 22b: flange 
                   21c, 22c: plate terminal 
                 
                 
                   22: second electrode terminal 
                   24: vent hole 
                 
                 
                   25: vent plate 
                   25a: notch 
                 
                 
                   27: sealing plug 
                   29: electrolyte injection opening 
                 
               
            
             
                 
                   36, 37: first and second electrode gaskets 
                 
               
            
             
                 
                   45: insulator 
                   46: top plate 
                 
               
            
             
                 
                   51, 52: first and second electrode lead tabs 
                 
                 
                   61, 62: first and second electrode insulation members 
                 
               
            
             
                 
                   100: unit ceils 
                   200: insulation member 
                 
                 
                   201: cell barrier 
                   202: opening 
                 
                 
                   203: upper edge 
                   300: cover 
                 
                 
                   301, 302: first and second openings 
                   303, 304: first and second drain 
                 
                 
                     
                   grooves 
                 
                 
                   400: cell sealing 
                   500: terminal sealing 
                 
                 
                   H1, H2: terminal hole 
                 
                 
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION 
       [0039]    In the following detailed description, certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. 
         [0040]      FIG. 1  is a perspective view of a rechargeable battery module according to an exemplary embodiment of the present invention, and  FIG. 2  is an exploded perspective view of the rechargeable battery module of  FIG. 1 . 
         [0041]    Referring to  FIGS. 1 and 2 , a rechargeable battery module according to an embodiment of the present invention includes unit cells  100  each forming a rechargeable battery, an insulation member  200  for receiving the unit cells  100 , and a cover  300  for covering the unit cells  100 . 
         [0042]    The insulation member  200  and the cover  300  are used for external insulation of the unit cells  100 , and may prevent or substantially prevent an external short circuit of the unit cells  100  due to an aqueous circuit formed by condensed water. That is, in one embodiment, the insulation member  200  and cover  300  have structures for individually insulating the unit cells  100 . 
         [0043]    In one embodiment, as shown in  FIG. 2 , the insulation member  200  may have a one-body structure in which each of the unit cells  100  is independently received and insulated. In this case, the cover  300  may individually cover the unit cells  100  while in contact with the insulation member  200 . 
         [0044]    The insulation member  200  may be formed in a one-body structure in which the unit cells  100  are independently received or in an individual structure in which the unit cells  100  are independently insulated. In either of the two cases, the cover  300  may alternatively be formed in a one-body structure (not shown) in which a plurality of the unit cells  100  is insulated. 
         [0045]    As shown in  FIGS. 1 and 2 , the insulation member  200 , in one embodiment, is formed as one body and has receiving spaces which are separated by cell barriers  201 , and may be formed in a flexible housing structure. 
         [0046]    Accordingly, openings  202  formed on the insulation member  200  may be expanded and then contracted when the unit cells  100  are inserted, thus enabling the unit cells  100  to be held. 
         [0047]    In one embodiment, the rechargeable battery module may further include cell sealings  400  between the insulation member  200  and the cover  300 . The cell sealings  400  are disposed around the unit cells  100 , respectively, so that the unit cells  100  may be sealed individually. 
         [0048]    In one embodiment, one insulation member  200  and one cover  300  are provided to one unit cell  100 . In this case, one cell sealing  400  seals the insulation member  200  for receiving the unit cell  100  from the cover  300  for covering the unit cell  100 . Accordingly, an external short circuit between neighboring unit cells  100  is prevented or substantially prevented. 
         [0049]      FIG. 3  is an exploded perspective view of a rechargeable battery according to an exemplary embodiment of the present invention, and  FIG. 4  is a cross-sectional view of the rechargeable battery of  FIG. 3 , taken along the line IV-IV, 
         [0050]    Referring to  FIGS. 3 and 4 , the unit cell  100  includes an electrode assembly  10  for charging and discharging currents, a case  15  for containing the electrode assembly  10 , a cap plate  20  sealing an opening of the case  15 , and a first electrode terminal  21  (e.g., a negative terminal) and a second electrode terminal  22  (e.g., a positive terminal) attached to the cap plate  20 , 
         [0051]    As in the rechargeable battery module described above, the unit cell  100  includes an insulation member  200  for receiving the unit cell  100 , and a cover  300  for covering the unit cell  100 . In one embodiment, the unit cell  100  may further include a cell sealing  400  provided between the insulation member  200  and the cover  300 , 
         [0052]    The electrode assembly  10  may be formed by disposing a first electrode  11  (e.g., a negative electrode) and a second electrode  12  (e.g., a positive electrode) at both sides of a separator  13 , which is an insulator, and winding the first electrode  11 , the separator  13 , and the second electrode  12  in a jelly roll shape. 
         [0053]    The first electrode  11  and the second electrode  12  include coated regions  11   a  and  12   a  and uncoated regions  11   b  and  12   b , respectively. The coated regions  11   a  and  12   a  are formed by applying an active material to a current collector of a metal plate, and the uncoated regions  11   b  and  12   b  are formed as an exposed current collector where the active material is not applied. 
         [0054]    In one embodiment, the uncoated region  11   b  of the first electrode  11  is formed at one end of the first electrode  11  along the first electrode  11 , which is wound, the uncoated region  12   b  of the second electrode  12  is formed at one end of the second electrode  12  along the second electrode  12 , which is wound, and the uncoated regions  11   b  and  12   b  are disposed at respective ends of the electrode assembly  10 . 
         [0055]    In one embodiment, the case  15  has an approximately cuboid shape, an inner space for receiving the electrode assembly  10  and electrolyte solution, and an opening formed at one side of the case  15  for connecting the inner space with the outside. The opening allows the electrode assembly  10  to be inserted into the case  15 . 
         [0056]    The cap plate  20  is attached to the case  15  at the opening to seal the case  15 . In one embodiment, the case  15  and the cap plate  20  are formed of aluminum and are welded together. 
         [0057]    In one embodiment, the cap plate  20  includes an electrolyte injection opening  29 , a vent hole  24 , and terminal holes H 1  and H 2 . The electrolyte solution may be injected into the case  15  through the electrolyte injection opening  29  after the cap plate  20  is combined with the case  15 . The electrolyte injection opening  29  may be sealed with a sealing plug  27  when the electrolyte solution is completely injected. 
         [0058]    The vent hole  24  may be closed and sealed with a vent plate  25  so as to release an internal pressure of the rechargeable battery. The vent plate  25  is cut or ruptured to open the vent hole  24  when the internal pressure reaches or exceeds a pressure (e.g., a predetermined pressure). The vent plate  25  may have a notch  25   a  for guiding the cut. 
         [0059]    The first terminal  21  and the second terminal  22  are connected through the terminal holes H 1  and H 2  of the cap plate  20  and electrically connected to the electrode assembly  10 . That is, the first electrode  21  is electrically connected to the first electrode  11  of the electrode assembly  10 , and the second terminal  22  is electrically connected to the second electrode  12  of the electrode assembly  10 . Accordingly, the electrode assembly  10  is drawn out to an outside of the case  15  through the first terminal  21  and the second terminal  22 . 
         [0060]    In one embodiment, the first and second terminals  21  and  22  include rivet terminals  21   a  and  22   a  attached to the terminal holes H 1  and H 2  of the cap plate  20 , flanges  21   b  and  22   b  formed integrally with the rivet terminals  21   a  and  22   a  inside the cap plate  20 , and plate terminals  21   c  and  22   c  disposed outside the cap plate  20  and connected with the rivet terminals  21   a  and  22   a , respectively, such as through riveting or welding. 
         [0061]    First and second electrode gaskets  36  and  37  are attached between the rivet terminals  21   a  and  22   a  of the first and second terminals  21  and  22  and the terminal holes H 1  and H 2 , respectively, of the cap plate  20 , thus sealing and electrically insulating the cap plate  20  from the rivet terminals  21   a  and  22   a  of the first and second terminals  21  and  22 , respectively. 
         [0062]    The first and second electrode gaskets  36  and  37 , in one embodiment, are extended and attached between the flanges  21   b  and  22   b  and an inner surface of the cap plate  20  to further seal and electrically insulate the flanges  21   b  and  22   b , respectively, from the cap plate  20 . The first and second electrode gaskets  36  and  37  prevent or substantially prevent leakage of the electrolyte solution through the terminal holes H 1  and H 2 , respectively, which may otherwise be caused by attaching the first and second terminals  21  and  22  to the cap plate  20 . 
         [0063]    First and second electrode lead tabs  51  and  52  electrically connect the first and second terminals  21  and  22  to the first and second electrodes  11  and  12  of the electrode assembly  10 , respectively. In one embodiment, the first and second electrode lead tabs  51  and  52  are connected to lower portions of the rivet terminals  21   a  and  22   a  to caulk the lower portions, respectively. Thus, in one embodiment, the first and second electrode lead tabs  51  and  52  are supported by the flange  21   b  and  22   b  and connected to the lower portions of the rivet terminals  21   a  and  22   a , respectively. 
         [0064]    In one embodiment, first and second electrode insulation members  61  and  62  are attached between the first and second electrode lead tabs  51  and  52  and the cap plate  20  to electrically insulate the first and second electrode lead tabs  51  and  52 , respectively, from the cap plate. 
         [0065]    In one embodiment, the first and second electrode insulation members  61  and  62  each have one side connected to the cap plate  20  and other sides surrounding the first and second electrode lead tabs  51  and  52 , the rivet terminals  21   a  and  22   a , and the flanges  21   b  and  22   b , respectively, thus stabilizing connection structures thereof. 
         [0066]    In one embodiment, an insulator  45  of the first terminal  21  is disposed between the cap plate  20  and the plate terminal  21   c  of the first terminal  21  and passes through the rivet terminal  21   a  to electrically insulate the plate terminal  21   c  from the cap plate  20 . 
         [0067]    The cap plate  20 , in one embodiment, has a receiving groove formed on an outer surface thereof and receives a lower portion of the insulator  45 , such that the insulator  45  and the first terminal  21  may be accurately located on the cap plate  20 . 
         [0068]    In one embodiment, the insulator  45  and the plate terminal  21   c  are connected to an upper portion of the rivet terminal  21   a  to caulk the upper portion of the rivet terminal  21   a . Thus, in one embodiment, the insulator  45  and the plate terminal  21   c  are coupled to the upper portion of the rivet terminal  21   a , such that the plate terminal  21   c  is attached outside the cap plate  20 , and the insulator  45  is disposed therebetween. 
         [0069]    The first electrode gasket  36 , in one embodiment, is extended between the rivet terminal  21   a  and the insulator  45  through the terminal hole H 1 . That is, in one embodiment, the first electrode gasket  36  electrically insulates the rivet terminal  21   a  from the cap plate  20 . 
         [0070]    In one embodiment, a top plate  46  of the second terminal  22  is disposed between the plate terminal  22   c  and the cap plate  20  and passes through the rivet terminal  22   a  to electrically connect the plate terminal  22   c  with the cap plate  20 . 
         [0071]    The cap plate  20 , in one embodiment, may have a receiving groove formed on the outer surface thereof and receiving a lower portion of the top plate  46 , such that the top plate  46  and the second terminal  22  may be accurately located on the cap plate  20 . 
         [0072]    In one embodiment, the top plate  46  and the plate terminal  22   c  are connected to an upper portion of the rivet terminal  22   a  to caulk the upper portion of the rivet terminal  22   a . Thus, in one embodiment, the top plate  46  and the plate terminal  22   c  are coupled to the upper portion of the rivet terminal  22   a , and the plate terminal  22   c  is attached outside the cap plate  20  while the top plate  46  is disposed therebetween. 
         [0073]    The second electrode gasket  37 , in one embodiment, is extended between the rivet terminal  22   a  and the top plate  46  through the terminal hole H 2 . That is, the second electrode gasket  37  prevents or substantially prevents the rivet terminal  22   a  and the top plate  46  from being electrically and directly connected, and the rivet terminal  22   a  is electrically connected to the top plate  46  through the plate terminal  22   c.    
         [0074]      FIG. 5  is a cross-sectional view of the rechargeable battery module of  FIG. 1 , taken along the line V-V. Referring to  FIGS. 3 to 5 , in one embodiment, the unit cell  100  may further include a terminal sealing  500  between the insulation member  200  and the cover  300 . The terminal sealing  500  is provided to seal the first terminal  21  or the second terminal  22  in the unit cell  100 , thus preventing or substantially preventing an external short circuit caused by an aqueous circuit. 
         [0075]    In one embodiment, in the unit cell  100 , the terminal sealing  500  is disposed around at least one of the first and second terminals  21  and  22  to seal the terminal. For convenience,  FIG. 5  illustrates a configuration in which the terminal sealing  500  is disposed outside the first terminal  21 . 
         [0076]    The cap plate  20  of the unit cell  100  is disposed at the opening  202  of the insulation member  200 , and an upper edge  203  forming the opening  202  of the insulation member  200  is disposed on the cap plate  20 . That is, the upper edge  203  of the insulation member  200  is disposed between the cap plate  20  and the cover  300  to insulate therebetween. 
         [0077]    The cell sealing  400 , in one embodiment, is disposed between the cap plate  20  and the cover  300 . The cell sealing  400  may be disposed between the cover  300  and the upper edge  203  of the insulation member  200  disposed on the cap plate  20  to block an aqueous circuit that may be formed from outside the unit cell  100  to inside the unit cell  100 . 
         [0078]    The terminal sealing  500 , in one embodiment, is disposed between the cap plate  20  and the cover  300 . The terminal sealing  500  may be disposed outside the insulator  45  to block an aqueous circuit that may be formed from the first terminal  21  to the second terminal  22  in the unit cell  100 . 
         [0079]    In one embodiment, the first terminal  21  has a dual sealing structure formed with the cell sealing  400  and the terminal sealing  500 , and the second terminal  22  has a single sealing structure formed with the cell sealing  400 . Accordingly, in the first terminal  21  and the second terminal  22  of neighboring unit cells  100 , an aqueous circuit is blocked by one terminal sealing  500  and two cell sealings  400 . 
         [0080]    The cover  300  is made of an electrically insulating material and covers the cap plate  20 . The cover  300 , in one embodiment, has receiving grooves for connecting the cell sealing  400  and the terminal sealing  500  to fix the cell sealing  400  and the terminal sealing  500  to positions thereof on the cap plate  20 . The cover  300 , in one embodiment, has a first opening  301  for exposing the first terminal  21  and a second opening  302  for exposing the second terminal  22 . The second opening  302  may be formed to further expose the vent hole  24  and the electrolyte injection opening  29 . 
         [0081]    The first opening  301  is connected with the insulator  45  of the first terminal  21 , and the second opening  302  is connected with the top plate  46  of the second terminal  22 . Accordingly, the cover  300  may be accurately located on the cap plate  20 . 
         [0082]    The cover  300 , in one embodiment, has a first drain groove  303  and a second drain groove  304  formed along or surrounding the first opening  301  and the second opening  302 , respectively, to drain condensed water. The first drain groove  303  may be formed at a side of the first opening  301  to guide water to one side of the insulation member  200 . The second drain groove  304  may be formed at an opposite side of the first drain groove  303  in the second opening  302  to guide water to another side of the insulation member  200 . 
         [0083]    In one embodiment, the first and second drain grooves  303  and  304  are formed in a curved surface toward the first and second terminals  21  and  22 , respectively, to facilitate collecting condensed water. The first and second drain grooves  303  and  304 , in one embodiment, are open at both sides in a lengthwise direction of the cap plate  20  to guide condensed water to both sides of the unit cell  100  and drain the condensed water to side surfaces of the insulation member  200 . 
         [0084]    The rechargeable battery module may be formed by disposing a bus bar (not shown) on the cover  300  and welding both ends of the bus bar with the plate terminals  21   c  and  22   c  of the first and second terminals  21  and  22 , respectively. The cell sealing  400  and the terminal sealing  500  may maintain the aqueous circuit being strongly blocked by a weld strength between the bus bar and the plate terminals  21   c  and  22   c.    
         [0085]    In one embodiment, the rechargeable battery may be formed by attaching cover  300  and the upper edge  203  of the insulation member  200  to the unit cell  100  with an adhesive (not shown). The cell sealing  400  and the terminal sealing  500  may maintain the aqueous circuit being strongly blocked by adherence of the adhesive. 
         [0086]      FIG. 6  is an exploded perspective view of a rechargeable battery according to another exemplary embodiment of the present invention. 
         [0087]    Referring to  FIG. 6 , a unit cell  100 ′ forming a rechargeable battery according to another embodiment of the present invention includes the electrode assembly  10 , the case  15  for containing the electrode assembly  10 , the cap plate  20  sealing an opening of the case  15 , and the first electrode terminal  21  (e.g., a negative terminal) and the second electrode terminal  22  (e.g., a positive terminal) attached to the cap plate  20 . As in the unit cell  100  described above, the unit cell  100 ′ includes the insulation member  200  for receiving the unit cell  100 ′, and a cover  300 ′ for covering the unit cell  100 ′. In one embodiment, the unit cell  100 ′ may further include the cell sealing  400  and the terminal sealing  500  provided between the insulation member  200  and the cover  300 ′. Like the cover  300  described above, the cover  300 ′, in one embodiment, includes the first and second openings  301  and  302 , and the first and second drain grooves  303  and  304 . The cover  300 ′ differs from the cover  300  described above in that the cover  300 ′ further includes a plurality of extending portions  305  extending from each side of the cover  300 ′ along a lengthwise direction of the cover  300 ′. The extending portions  305  extend from a surface of the cover  300 ′ that is facing the cap plate  20  and are coupled to the unit cell  100 ′. In one embodiment, the extending portions  305  are coupled to lateral side surfaces of the insulation member  200 . 
         [0088]      FIG. 7  is an exploded perspective view of a rechargeable battery according to another exemplary embodiment of the present invention. 
         [0089]    Referring to  FIG. 7 , a unit cell  100 ″ forming a rechargeable battery according to another embodiment of the present invention is substantially similar to the unit cell  100 ′ described above and shown in  FIG. 6 . The unit cell  100 ″, however, includes a cover  300 ″ that differs from the cover  300 ′ described above in that the cover  300 ″ includes a single continuous extending portion  306  extending from each side of the cover  300 ″ along a lengthwise direction of the cover  300 ″. The extending portions  306  extend from a surface of the cover  300 ″ that is facing the cap plate  20  and are coupled to the unit cell  100 ″. In one embodiment, the extending portions  306  are coupled to lateral side surfaces of the insulation member  200 . 
         [0090]      FIG. 8  is an exploded perspective view of a rechargeable battery module according to another exemplary embodiment of the present invention. 
         [0091]    Referring to  FIG. 8 , a rechargeable battery module according to another embodiment of the present invention includes unit cells  100  each forming a rechargeable battery, the insulation member  200  for receiving the unit cells  100 , and a cover  600  for covering the unit cells  100 . The cover  600  is formed in a one-body structure in which a plurality of the unit cells  100  is insulated. The cover  600 , in one embodiment, has an opening  601  for exposing the first terminals  21  and the second terminals  22  of the plurality of unit cells  100 , and a drain groove  603  formed along or surrounding the opening  601  to drain condensed water. The rechargeable battery may further include the cell sealings  400  and the terminal sealings  500  between the insulation member  200  and the cover  600 . 
         [0092]    While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.