Abstract:
A rechargeable battery includes: a plurality of electrode assemblies each including first and second electrodes; a case accommodating the electrode assemblies; a cap assembly coupled to the case and including a terminal; and a first current collector coupling the terminal with the first electrodes of the electrode assemblies. The first current collector includes a terminal connector coupled to the terminal and a plurality of electrode connectors, each of the electrode connectors being coupled to a respective one of the first electrodes, and a plurality of first fuses, each of the first fuses being between the terminal connector and a respective one of the electrode connectors and having a substantially constant cross section between the terminal connector and the respective one of the electrode connectors.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2013-0141613, filed in the Korean Intellectual Property Office on Nov. 20, 2013, the contents of which are incorporated herein by reference in their entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Aspects of embodiments of the present invention relate generally to a rechargeable battery. 
         [0004]    2. Description of the Related Art 
         [0005]    A rechargeable battery differs from a primary battery in that it is designed to be repeatedly charged and discharged, while the latter is not designed to be recharged. 
         [0006]    A low-capacity rechargeable battery is used in small portable electronic devices, such as mobile phones, notebook computers, and camcorders, while a high-capacity rechargeable battery is widely used as a power source for driving a motor of a hybrid vehicle and the like. 
         [0007]    Recently, a high power rechargeable battery using a non-aqueous electrolyte and having high energy density has been developed, and the high power rechargeable battery is formed by coupling a plurality of rechargeable batteries in series to be used as a power source for driving a motor of a device requiring a large amount of electric power, for example, an electric vehicle and the like. 
         [0008]    In addition, a high-capacity battery module generally includes a plurality of rechargeable batteries connected in series, and the rechargeable batteries may be formed in a cylindrical or prismatic shape. 
         [0009]    When a short circuit occurs due to internal reasons or contact by external materials and/or objects, an overcurrent flows in the rechargeable battery and/or rechargeable batteries. 
         [0010]    When the overcurrent continuously flows, the rechargeable battery may explode or catch fire due to excessive heat generated inside of the rechargeable battery. 
         [0011]    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 known to a person of ordinary skill in the art. 
       SUMMARY 
       [0012]    Aspects of embodiments of the present invention have been made in an effort to provide a rechargeable battery which is capable of stably cutting off a current when internal and/or external short circuits occur. 
         [0013]    A rechargeable battery according to an example embodiment includes: a plurality of electrode assemblies each including a first electrode and a second electrode; a case accommodating the electrode assemblies; a cap assembly coupled to the case and including a terminal; and a first current collector coupling the terminal with the first electrodes of the electrode assemblies, wherein the first current collector includes a terminal connector coupled to the terminal, a plurality of electrode connectors, each of the electrode connectors being coupled to a respective one of the first electrodes, and a plurality of first fuses, each of the first fuses being between the terminal connector and a respective one of the electrode connectors and having a substantially constant cross section between the terminal connector and the respective one of the electrode connectors. 
         [0014]    The plurality of first fuses may extend along a length direction of the electrode connectors. 
         [0015]    Each of the first fuses may protrude from the terminal connector, and the electrode connectors may extend from the first fuses. 
         [0016]    Each of the first fuses may have a cross-section smaller than that of a portion of the first current collector adjacent the first fuses. 
         [0017]    The first fuses may include a material having a melting point lower than that of a portion of the first current collector adjacent the first fuses. 
         [0018]    The first current collector may further include a second fuse coupling the electrode connectors to each other and may be located between the electrode connectors. 
         [0019]    The first fuses and the second fuse may be configured to melt in sequence when an overcurrent flows. 
         [0020]    The second fuse may be closer to the electrode connectors than each of the first fuses is to the electrode connectors. 
         [0021]    The second fuse may couple the electrode connectors to each other. 
         [0022]    The first current collector may further include a third fuse located between the first fuses, the first fuses may be coupled to each other through the third fuse, and each of the first fuses may be closer to the electrode connectors than the third fuse is to the electrode connectors. 
         [0023]    The third fuse may extend between the first fuses to couple lateral ends of the first fuses to each other. 
         [0024]    The first current collector may further include a plurality of fourth fuses coupled to the terminal connector, and the first fuses may be electrically coupled to the terminal connector through the fourth fuses. 
         [0025]    The first fuses may be coupled to the fourth fuses. 
         [0026]    The third fuse may have a width smaller than that of each of the first fuses. 
         [0027]    Each of the fourth fuses may be coupled to each of the electrode connectors, and each of the fourth fuses may have a width smaller than that of each of the first fuses. 
         [0028]    The third fuse and the fourth fuses may be configured to melt before the first fuses when an overcurrent flows. 
         [0029]    The first current collector may include a greater number of first fuses than fourth fuses, and each of the fourth fuses may have a width greater than that of each of the first fuses. 
         [0030]    The width of each of the fourth fuses may be less than two times the width of each of the first fuses. 
         [0031]    A width of the third fuse may be less than the width of each of the first fuses. 
         [0032]    A width of the third fuse at a center region of the third fuse may be less than a width of the third fuse outside the center region. 
         [0033]    Because the plurality of fuses are coupled (e.g., connected) in series or in parallel, the example embodiment may cut off the current flowing from one electrode assembly to another electrode assembly when the short-circuit occurs. 
         [0034]    In addition, it may cut off the current flowing from the electrode assembly to the terminal when the external short-circuit occurs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]      FIG. 1  is a perspective view of a rechargeable battery according to a first example embodiment of the present invention. 
           [0036]      FIG. 2  is a cross-sectional view of  FIG. 1  taken along the line II-II. 
           [0037]      FIG. 3  is an exploded perspective view of electrode assemblies and current collecting members according to the first example embodiment of the present invention. 
           [0038]      FIG. 4  is a side view of a first current collecting member according to the first example embodiment of the present invention. 
           [0039]      FIG. 5  is an exploded perspective view of electrode assemblies and current collecting members according to a second example embodiment of the present invention. 
           [0040]      FIG. 6  is a side view of a first current collecting member according to the second example embodiment of the present invention. 
           [0041]      FIG. 7  is a perspective view of a first current collecting member according to a third example embodiment of the present invention. 
           [0042]      FIG. 8  is a side view of the first current collecting member according to the third example embodiment of the present invention. 
           [0043]      FIG. 9  is a perspective view of a first current collecting member according to a fourth example embodiment of the present invention. 
           [0044]      FIG. 10  is a side view of the first current collecting member according to the fourth example embodiment of the present invention. 
           [0045]      FIG. 11  is a perspective view of a first current collecting member according to a fifth example embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the invention are shown. 
         [0047]    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. 
         [0048]    Like reference numerals designate like elements throughout the specification and the drawings. Further, the use of “may” refers to “one or more embodiments of the present invention.” 
         [0049]      FIG. 1  is a perspective view of a rechargeable battery according to a first example embodiment of the present invention, and  FIG. 2  is a cross-sectional view of  FIG. 1  taken along the line II-II. 
         [0050]    Referring to  FIGS. 1 and 2 , the rechargeable battery  101  according to an example embodiment of the present invention includes an electrode assembly  10  formed by winding a positive electrode (e.g., a first electrode)  11  and a negative electrode (e.g., a second electrode)  12  with a separator  13  interposed therebetween, a case  26  in which the electrode assembly  10  is placed (e.g., is accommodated), and a cap assembly  30  combined to (e.g., joined at) an opening in the case  26 . 
         [0051]    The rechargeable battery  101  according to the present example embodiment is illustrated as a prismatic, lithium ion rechargeable battery as an example. 
         [0052]    However, the present invention is not limited thereto, and aspects of embodiments of the present invention can be applied to batteries of various kinds and shapes, such as a lithium polymer battery, a cylindrical battery, and the like. 
         [0053]    The positive electrode  11  and the negative electrode  12  each include coated regions where an active material is coated on a current collector formed of a thin metal foil and uncoated regions  11   a  and  12   a  where the active material is not coated thereon. 
         [0054]    The positive electrode uncoated region  11   a  is formed at one lateral end of the electrode assembly  10  (e.g., at one lateral end of the positive electrode  11 ) along a length direction thereof, and the negative electrode uncoated region  12   a  is formed at the other lateral end of the electrode assembly  10  (e.g., at one lateral end of the negative electrode  12 ) along the length direction thereof. 
         [0055]    The positive electrode  11  and the negative electrode  12  are wound with the separator  13 , which operates as an insulator, interposed between them. 
         [0056]    However, the present invention is not limited thereto, and the electrode assembly  10  may have a layered structure in which a negative electrode and a positive electrode, respectively formed of a plurality of sheets, are layered with a separator between them. 
         [0057]    The case  26  is roughly formed in a shape of a cuboid, and an opening is formed at one side thereof. 
         [0058]    The case  26  may be made of a metal, such as aluminum, stainless steel, and the like. 
         [0059]    The cap assembly  30  includes a cap plate  31  covering the opening of the case  26 , a first terminal  21  protruding out of the cap plate  31  and electrically coupled to (e.g., electrically connected to) the positive electrode  11 , and a second terminal  22  protruding out of the cap plate  31  and electrically coupled to the negative electrode  12 . 
         [0060]    The cap plate  31  is formed in an elongated plate shape extending in one direction and is combined to (e.g., joined at) the opening of the case  26 . 
         [0061]    The cap plate  31  includes a sealing cap  38  provided in (e.g., sealing) an electrolyte injection opening  32  and a vent plate  39  which is provided in a vent opening  34  (e.g., a vent hole) and is formed with a notch  39   a  set to be opened at a reference pressure (e.g., a predetermined pressure). 
         [0062]    The first and second terminals  21  and  22  are provided to protrude upwards from the cap plate  31 . 
         [0063]    The first terminal  21  is electrically coupled to the positive electrode  11  through a first current collecting member  41 , and the second terminal  22  is electrically coupled to the negative electrode  12  through a second current collecting member  42 . 
         [0064]    However, the present invention is not limited thereto, and the first terminal  21  may be electrically coupled to the negative electrode, while the second terminal  22  may be electrically coupled to the positive electrode. 
         [0065]    The first terminal  21  has a rectangular plate shape. 
         [0066]    The first terminal  21  is electrically coupled to the positive electrode  11  through a connecting terminal  25  coupled to (e.g., bonded to) the first current collecting member  41 . 
         [0067]    The connecting terminal  25  combined with (e.g., joined with) the first terminal  21  has the same or substantially the same structure as the connecting terminal  25  combined with the second terminal  22 . 
         [0068]    A sealing gasket  59  for sealing is provided between the connecting terminal  25  and the cap plate  31  to be inserted into an opening (e.g., a hole) in the cap plate  31  that the connecting terminal  25  penetrates, and a lower insulation member  43  is provided under the cap plate  31  to support the current collecting member  41  from above. 
         [0069]    A connection member  58  electrically coupling the first terminal  21  and the cap plate  31  is provided under the first terminal  21 . 
         [0070]    Accordingly, the cap plate  31  and the case  26  are coupled to the positive electrode  11 . 
         [0071]    The second terminal  22  has a rectangular plate shape. 
         [0072]    The second terminal  22  is electrically coupled to the negative electrode  12  through the connecting terminal  25  which is coupled to (e.g., bonded to) the second current collecting member  42 . 
         [0073]    The connecting terminal  25  penetrates through (e.g., extends through) the cap plate  31  and the second terminal  22  such that its upper part is fixed to the second terminal  22 . 
         [0074]    A sealing gasket  55  for sealing is provided between the second terminal  22  and the cap plate  31  to be inserted into an opening (e.g., a hole) in the cap plate  31  that the second terminal  22  penetrates, and a lower insulation member  45  is provided under the cap plate  31  to insulate the second terminal  22  from the second current collecting member  42  at the cap plate  31 . 
         [0075]    A short-circuit protrusion is formed to protrude towards a short-circuit opening  37  (e.g., a short circuit hole) at a bottom side of the second terminal  22 . 
         [0076]    The second terminal  22  is formed to be elongated in one direction to cover the short-circuit opening  37 . 
         [0077]    An upper insulation member  54  is provided between the second terminal  22  and the cap plate  31  to electrically insulate them from each other. 
         [0078]    Because the cap assembly  30  includes a short-circuit member  56  which short-circuits the positive electrode  11  and the negative electrode  12 , the short-circuit member  56  is electrically coupled to the cap plate  31  and deforms to be connected to the second terminal  22  when internal pressure of the rechargeable battery  101  increases. 
         [0079]    The short-circuit opening  37  is formed in the cap plate  31 , and the short-circuit member  56  is disposed between the upper insulation member  54  and the cap plate  31  in the short-circuit opening  37 . 
         [0080]    The short-circuit member  56  includes a curved portion which is convexly curved downwards in an arc shape and an edge portion which is formed outside of (e.g., which surrounds) the curved portion and is fixed to the cap plate  31 . 
         [0081]    When gas is generated by an abnormal reaction inside the rechargeable battery  101 , internal pressure of the rechargeable battery  101  increases. 
         [0082]    The curved portion of the short-circuit member  56  deforms to be convexly curved upwards when internal pressure of the rechargeable battery  101  exceeds a reference level (e.g., a predetermined level), and in this case, the short-circuit protrusion contacts the short-circuit member  56  to cause a short circuit. 
         [0083]      FIG. 3  is an exploded perspective view of electrode assemblies and current collecting members according to the first example embodiment of the present invention, and  FIG. 4  is a side view of a first current collecting member according to the first example embodiment of the present invention. 
         [0084]    Referring to  FIGS. 3 and 4 , the first current collecting member  41  includes a terminal connection portion  41   a  coupled to (e.g., bonded to) the connecting terminal  25  and electrode connection portions  41   b  extending from the terminal connection portion  41   a  towards a bottom of the case  26 . 
         [0085]    The terminal connection portion  41   a  has a quadrangular plate shape and is coupled to (e.g., fixed to) a bottom side of the connecting terminal  25  by, for example, welding. 
         [0086]    A fastening opening  41   d  (e.g., a fastening hole) is formed in the terminal connection portion  41   a , and the terminal connection portion  41   a  is welded to the connecting terminal  25  while a protrusion formed at the bottom of the connecting terminal  25  is inserted into (e.g., fitted into) the fastening opening  41   d.    
         [0087]    Two electrode assemblies  10  are inserted into the case  26  to be disposed in parallel with each other, and the first current collecting member  41  is provided with two electrode connection portions  41   b.    
         [0088]    Each of the electrode connection portions  41   b  is bent from a first fuse portion  41   c  to be coupled to (e.g., bonded to) the positive electrode uncoated region  11   a  while being disposed in parallel therewith. 
         [0089]    The electrode connection portions  41   b  are respectively coupled to the positive electrode uncoated regions  11   a  of the different electrode assemblies  10  by, for example, welding. 
         [0090]    The first fuse portions  41   c  are formed between the electrode connection portion  41   b  and the terminal connection portion  41   a  such that they are melted faster (e.g., are melted or become disconnected in a shorter amount of time) than respective peripheral regions when an overcurrent flows. 
         [0091]    The first fuse portions  41   c  are bent from the terminal connection portion  41   a  to protrude towards the bottom of the case  26 . 
         [0092]    The two first fuse portions  41   c  are formed at the terminal connection portion  41   a , and the first fuse portions  41   c  have smaller cross-sections than the respective peripheral regions. 
         [0093]    The electrode connection portions  41   b  are coupled to the terminal connection portion  41   a  through the first fuse portions  41   c , and each of the first fuse portions  41   c  is coupled to each of the electrode connection portions  41   b . The first fuse portions  41   c  have a substantially constant cross section between the terminal connection portion  41   a  and respective ones of the electrode connection portions  41   b.    
         [0094]    The first fuse portions  41   c  are disposed in series with (e.g., in line with) the electrode connection portions  41   b . The first fuse portions  41   c  extend along a length direction of the electrode connection portions  41   b.    
         [0095]    A second current collecting member  42  includes a terminal connection portion  42   a  coupled to (e.g., bonded to) the connecting terminal  25  and electrode connection portions  42   b  extending from the terminal connection portion  42   a  towards the bottom of the case  26 . 
         [0096]    A fastening opening  42   d  (e.g., a fastening hole) is formed in the terminal connection portion  42   a , and the terminal connection portion is coupled to (e.g., bonded to) the connecting terminal  25  by, for example, welding while a protrusion formed at a bottom of the connecting terminal  25  is inserted into (e.g., fitted into) the fastening opening  42   d.    
         [0097]    The electrode connection portions  42   b  are bent from first fuse portions  42   c  to be coupled to (e.g., bonded to) the negative electrode uncoated region  12   a  by, for example, welding while being disposed in parallel therewith. 
         [0098]    The electrode connection portions  42   b  are respectively coupled to the negative electrode uncoated regions  12   a  of the different electrode assemblies  10  by, for example, welding. 
         [0099]    The first fuse portions  42   c  are formed between the electrode connection portions  42   b  and the terminal connection portion  42   a  such that they are melted faster (e.g., melt or become disconnected in a shorter amount of time) than respective peripheral regions when an overcurrent flows. 
         [0100]    The first fuse portions  42   c  are formed to have a smaller cross-section than the respective peripheral regions, and the electrode connection portions  42   b  are coupled to the terminal connection portion  42   a  through the first fuse portions  42   c.    
         [0101]    When an internal short-circuit occurs in one of the electrode assemblies  10 , short-circuit current flows from the other electrode assembly  10  to the short-circuited electrode assembly  10 . 
         [0102]    The short-circuit current flows through the electrode connection portions  41   b  and  42   b  and the first fuse portions  41   c  and  42   c , and the first fuse portions  41   c  and  42   c  are melted when the short-circuit current flows, thereby cutting off the short-circuit current. 
         [0103]    In addition, when an external short-circuit occurs due to, for example, the deformed short-circuit member  56  (e.g., when the short-circuit member  56  deforms), a short-circuit current flows from each of the electrode assemblies  10  to the terminals  21  and  22 , and the short-circuit current flows to the terminals  21  and  22  through the first fuse portions  41   c  and  42   c.    
         [0104]    Accordingly, the first fuse portions  41   c  and  42   c  may cut off the short-circuit current by melting when the short-circuit current flows. 
         [0105]      FIG. 5  is an exploded perspective view of electrode assemblies and current collecting members according to a second example embodiment of the present invention, and  FIG. 6  is a side view of a first current collecting member according to the second example embodiment of the present invention. 
         [0106]    Referring to  FIGS. 5 and 6 , because a rechargeable battery according to the present example embodiment has the same or substantially the same structure as the first example embodiment described above, except for a structure of first and second current collecting members  61  and  62 , a repeated description of the structure may be omitted. 
         [0107]    The first current collecting member  61  includes a terminal connection portion  61   a  coupled to (e.g., bonded to) the connecting terminal  25  and electrode connection portions  61   b  extending from the terminal connection portion  61   a  towards the bottom of the case  26 . 
         [0108]    The terminal connection portion  61   a  has a quadrangular plate shape and is coupled to (e.g., fixed to) the bottom of the connecting terminal  25  by, for example, welding. 
         [0109]    A fastening opening  61   d  (e.g., a fastening hole) is formed in the terminal connection portion  61   a , and the terminal connection portion  61   a  is welded to the connecting terminal  25  while the protrusion formed at the bottom of the connecting terminal  25  is inserted into (e.g., fitted into) the fastening opening  61   d.    
         [0110]    Two electrode assemblies  10  are disposed in parallel with each other in the case  26 , and the first current collecting member  61  is provided with two electrode connection portions  61   b.    
         [0111]    The electrode connection portions  61   b  are bent from first fuse portions  61   c  and are coupled to (e.g., bonded to) the positive electrode uncoated region  11   a  while being disposed in parallel therewith. 
         [0112]    The electrode connection portions  61   b  are respectively coupled to (e.g., bonded to) the positive electrode uncoated regions  11   a  of the different electrode assemblies  10  by, for example, welding. 
         [0113]    The first fuse portions  61   c  are formed between the electrode connection portions  61   b  and the terminal connection portion  61   a  such that they are melted faster than respective peripheral regions when an overcurrent flows. 
         [0114]    The first fuse portions  61   c  are bent from the terminal connection portion  61   a  to protrude toward the bottom of the case  26 . 
         [0115]    The two first fuse portions  61   c  are formed at the terminal connection portion  61   a , and the first fuse portions  61   c  have smaller cross-sections than the respective peripheral regions. 
         [0116]    The electrode connection portions  61   b  are coupled to the terminal connection portion  61   a  through the first fuse portions  61   c , and each of the first fuse portions  61   c  is coupled to each of the electrode connection portions  61   b.    
         [0117]    The first fuse portions  61   c  are disposed in series with (e.g., in line with) the electrode connection portions  61   b.    
         [0118]    A second fuse portion  61   e  is formed between (e.g., extends between) the electrode connection portions  61   b  to directly couple (e.g., directly connect) the electrode connection portions  61   b  to each other. 
         [0119]    Opposite ends (e.g., lateral ends) of the second fuse portion  61   e  are respectively coupled to the electrode connection portions  61   b.    
         [0120]    The second fuse portion  61   e  has a smaller cross-section than a peripheral region such that it is melted faster than its peripheral region when an overcurrent flows. 
         [0121]    The second fuse portion  61   e  is disposed closer to the electrode connection portions  61   b  than the first fuse portion  61   c  is, and the electrode connection portions  61   b  are coupled in parallel with each other through the second fuse portion  61   e.    
         [0122]    A second current collecting member  62  includes a terminal connection portion  62   a  coupled to (e.g., bonded to) the connecting terminal  25  and electrode connection portions  62   b  extending from the terminal connection portion  62   a  towards the bottom of the case  26 . 
         [0123]    A fastening opening  62   d  (e.g., a fastening hole) is formed at the terminal connection portion  62   a , and the terminal connection portion  62   a  is welded to the connecting terminal  25  while the protrusion formed at the bottom of the connecting terminal  25  is inserted into (e.g., fitted into) the fastening opening  62   d.    
         [0124]    The electrode connection portions  62   b  are bent from a first fuse portion  62   c  to be coupled to (e.g., bonded to) the negative electrode uncoated region  12   a  while being disposed in parallel therewith. 
         [0125]    The electrode connection portions  62   b  are respectively coupled to (e.g., bonded to) the negative electrode uncoated regions  12   a  of the different electrode assemblies  10  by, for example, welding. 
         [0126]    The first fuse portions  62   c  are formed between the electrode connection portions  62   b  and the terminal connection portion  62   a  such that they are melted faster than respective peripheral regions when an overcurrent flows. 
         [0127]    The first fuse portions  62   c  are formed to have a smaller cross-section than the respective peripheral regions, and the electrode connection portions  62   b  are coupled to the terminal connection portion  62   a  through the first fuse portions  62   c.    
         [0128]    A second fuse portion  62   e  is formed between (e.g., extends between) the electrode connection portions  62   b  to directly couple (e.g., directly connect) the electrode connection portions  62   b  to each other. 
         [0129]    The second fuse portion  62   e  is coupled to respective lateral ends of the electrode connection portions  62   b  such that it is disposed to cross the electrode connection portions  62   b.    
         [0130]    The second fuse portion  62   e  has a smaller cross-section such that it is melted faster than a periphery region when an overcurrent flows. 
         [0131]    The second fuse portion  62   e  is disposed closer to the electrode connection portions  62   b  than the first fuse portions  62   c  is. 
         [0132]    When an internal short-circuit occurs in one of the electrode assemblies  10 , a short-circuit current flows from the other electrode assembly  10  to the short-circuited electrode assembly  10 . 
         [0133]    The short-circuit current flows from the electrode connection portions  61   b  and  62   b  to the second fuse portions  61   e  and  62   e , and the second fuse portions  61   c  and  62   c  are melted when the short-circuit current flows. 
         [0134]    After the second fuse portions  61   e  and  62   e  are melted, the short-circuit current flows from the electrode connection portions  61   b  and  62   b  to the first fuse portions  61   c  and  62   c , and in this case, the first fuse portions  61   c  and  62   c  are melted. 
         [0135]    Accordingly, when the second fuse portions  61   e  and  62   e  are formed, the fuse portions are melted in sequence to reduce arc generation when the short-circuit occurs. 
         [0136]    In addition, structural stability of the current collecting member is improved as the second fuse portions  61   e  and  62   e  support the first fuse portions  61   c  and  62   c.    
         [0137]      FIG. 7  is a perspective view of a first current collecting member according to a third example embodiment of the present invention, and  FIG. 8  is a side view of the first current collecting member according to the third example embodiment of the present invention. 
         [0138]    Referring to  FIGS. 7 and 8 , because a rechargeable battery according to the present example embodiment has the same or substantially the same structure as the first example embodiment described above, except for a structure of a first current collecting member  63 , a repeated description of the structure may be omitted. 
         [0139]    The first current collecting member  63  includes a terminal connection portion  63   a  coupled to (e.g., bonded to) the connecting terminal  25  and electrode connection portions  63   b  extending from the terminal connection portion  63   a  towards the bottom of the case  26 . 
         [0140]    The terminal connection portion  63   a  has a quadrangular plate shape and is coupled to (e.g., fixed to) the bottom of the connecting terminal  25  by, for example, welding. 
         [0141]    A fastening opening  63   d  (e.g., a fastening hole) is formed in the terminal connection portion  63   a , and the terminal connection portion  63   a  is welded to the connecting terminal  25  while the protrusion formed at the bottom of the connecting terminal  25  is inserted into (e.g., fitted into) the fastening opening  63   d.    
         [0142]    Two electrode assemblies  10  are disposed in parallel with each other in the case  26 , and the first current collecting member  63  is provided with two electrode connection portions  63   b.    
         [0143]    The electrode connection portions  63   b  are bent from a first fuse portion  63   c  to be coupled to (e.g., bonded to) the positive electrode uncoated region  11   a  while being disposed in parallel therewith. 
         [0144]    The electrode connection portions  63   b  are respectively coupled to (e.g., bonded to) the positive electrode uncoated regions  11   a  of the different electrode assemblies  10  by, for example, welding. 
         [0145]    The first fuse portions  63   c  are formed between (e.g., extend between) the electrode connection portions  63   b  and the terminal connection portion  63   a  such that they are melted faster than respective peripheral regions when an overcurrent flows. 
         [0146]    The first fuse portions  63   c  are bent from the terminal connection portion  63   a  to protrude towards the bottom of the case  26 . 
         [0147]    The two first fuse portions  63   c  are formed at the terminal connection portion  63   a , and the first fuse portions  63   c  have smaller cross-sections than the respective peripheral regions. 
         [0148]    The electrode connection portions  63   b  are coupled to the terminal connection portion  63   a  through the first fuse portions  63   c , and each of the first fuse portions  63   c  is coupled to each of the electrode connection portions  63   b.    
         [0149]    The first fuse portions  63   c  are disposed in series with (e.g., in line with) the electrode connection portions  63   b.    
         [0150]    A third fuse portion  63   e  is formed to couple the first fuse portions  63   c  to each other such that it extends in a crossing direction of the first fuse portions  63   c  (e.g., the third fuse portion  63   e  extends between the first fuse portions  63   c ). 
         [0151]    The third fuse portion  63   e  is coupled to lateral ends of the first fuse portions  63   c  such that it electrically couples the first fuse portions  63   c  to each other. 
         [0152]    The third fuse portion  63   e  is disposed above the first fuse portions  63   c , and the first fuse portions  63   c  are disposed closer to the electrode connection portions  63   b  than the third fuse portion  63   e  is. Fourth fuse portions  63   f  are formed between the first fuse portions  63   c  and the terminal connection portion  63   a  such that they are disposed in series to be coupled with the first fuse portions  63   c.    
         [0153]    The first fuse portions  63   c  are coupled to the terminal connection portion  63   a  through the fourth fuse portions  63   c , and each of the fourth fuse portions  63   f  is coupled to each of the first fuse portion  63   c.    
         [0154]    The fourth fuse portions  63   f  are disposed above the first fuse portions  63   c , and the third fuse portion  63   e  is disposed between the fourth fuse portions  63   f  and the first fuse portions  63   c.    
         [0155]    In addition, the first fuse portions  63   c  are disposed closer to the electrode connection portions  63   b  than the fourth fuse portions  63   f  is. 
         [0156]    A width W4 of each of the fourth fuse portions  63   f  is smaller than a width W1 of each of the first fuse portions  63   c.    
         [0157]    In addition, a width W3 of the third fuse portion  63   e  (e.g., a width of a portion of the third fuse portion  63   e ) is smaller than the width W1 of the first fuse portion  63   c.    
         [0158]    Accordingly, the third and fourth fuse portions  63   e  and  63   f  are melted faster than the first fuse portion  63   c.    
         [0159]    When an internal short-circuit occurs in one of the electrode assemblies  10 , a short-circuit current flows from the other electrode assembly  10  to the short-circuited electrode assembly  10 . 
         [0160]    The short-circuit current flows through the first fuse portions  63   c  and the electrode connection portions  63   b , and the first fuse portions  63   c  are melted when the short-circuit current flows. 
         [0161]    However, when the first fuse portion  63   c  is not completely melted, the current flows through the third fuse portion  63   e , and in this case, the third fuse portion  63   e  is melted. 
         [0162]    Moreover, the short-circuit current flows through the fourth fuse portions  63   f  after the third fuse portion  63   e  is melted, and the fourth fuse portions  63   f  are melted as a result. 
         [0163]    When an external short-circuit occurs, the current flows through the first fuse portions  63   c  and the fourth fuse portions  63   f , and the fourth fuse portions  63   f  are melted due to the short-circuit current. 
         [0164]    Thus, the short-circuit current may be stably cut off. 
         [0165]      FIG. 9  is a perspective view of a first current collecting member according to a fourth example embodiment of the present invention, and  FIG. 10  is a side view of the first current collecting member according to the fourth example embodiment of the present invention. 
         [0166]    Referring to  FIGS. 9 and 10 , because a rechargeable battery according to the present example embodiment has the same or substantially the same structure as the first example embodiment described above, except for a structure of a first current collecting member  65  and a number of electrode assemblies  10  placed in the case, a repeated description of the structure may be omitted. 
         [0167]    Because a second current collecting member has the same or substantially the same structure as a first current collecting member  65 , a description of the second current collecting member may be omitted. 
         [0168]    Four electrode assemblies  10  are placed in the case  26 , and the electrode assemblies  10  are disposed in parallel (e.g., arranged) such that their flat frontal sides face each other. 
         [0169]    The first current collecting member  65  includes a terminal connection portion  65   a  coupled to (e.g., bonded to) the connecting terminal  25  and electrode connection portions  65   b  extending from the terminal connection portion  65   a  toward the bottom of the case  26 . 
         [0170]    The terminal connection portion  65   a  has a quadrangular plate shape and is coupled to (e.g., fixed to) the bottom side of the connecting terminal  25  by, for example, welding. 
         [0171]    A fastening opening  65   d  (e.g., a fastening hole) is formed in the terminal connection portion  65   a , and the terminal connection portion  65   a  is welded to the connecting terminal  25  while the protrusion formed at the bottom of the connecting terminal  25  is inserted into (e.g., fitted into) the fastening opening  65   d.    
         [0172]    The first current collecting member  65  has four electrode connection portions  65   b , and the four electrode connection portions  65   b  are coupled to the respective different electrode assemblies  10 . 
         [0173]    The electrode connection portions  65   b  are bent from first fuse portions  65   c  to be coupled to (e.g., bonded to) the positive electrode uncoated region  11   a  while being disposed in parallel therewith. 
         [0174]    The electrode connection portions  65   b  are respectively coupled to (e.g., bonded to) the positive electrode uncoated regions  11   a  of the different electrode assemblies  10  by, for example, welding. 
         [0175]    The first fuse portions  65   c  are formed between the electrode connection portions  65   b  and the terminal connection portion  61   a  such that they are melted faster than respective peripheral regions when an overcurrent flows. 
         [0176]    The first fuse portions  65   c  are bent from the terminal connection portion  65   a  to protrude towards the bottom of the case  26 . 
         [0177]    The four first fuse portions  65   c  are formed at the terminal connection portion  65   a , and the first fuse portions  65   c  have smaller cross-sections than the respective peripheral regions. 
         [0178]    The electrode connection portions  65   b  are coupled to the terminal connection portion  65   a  through the first fuse portions  65   c , and each of the first fuse portions  65   c  is coupled to each of the electrode connection portions  65   b.    
         [0179]    The first fuse portions  65   c  are disposed in series with (e.g., in line with) the electrode connection portions  65   b.    
         [0180]    A third fuse portion  65   e  is formed to couple the first fuse portions  65   c  to each other such that it extends in a crossing direction of the first fuse portions  65   c  (e.g., the third fuse portion  65   e  extends between each of the first fuse portions  65   c ). 
         [0181]    The third fuse portion  65   e  is coupled to lateral ends of the first fuse portions  65   c  such that it electrically couples the first fuse portions  65   c  to each other. 
         [0182]    The third fuse portion  65   e  is disposed above the first fuse portions  65   c , and the first fuse portions  65   c  are disposed closer to the electrode connection portions  65   b  than the third fuse portion  65   e  is. 
         [0183]    Two fourth fuse portions  65   f  are formed at the terminal connection portion  65   a  such that they are disposed between the first fuse portions  65   c  and the terminal connection portion  65   a.    
         [0184]    Accordingly, the first current collecting member  65  has more first fuse portions  65   c  than it has fourth fuse portions  65   f  (e.g., the first current collecting member  65  may include a greater number of first fuse portions  65   c  than fourth fuse portions  65   f ). 
         [0185]    The fourth fuse portions  65   f  are disposed above the first fuse portions  65   c , and the third fuse portion  65   e  is disposed between the first and fourth fuse portions  65   f  and  65   c.    
         [0186]    In addition, the first fuse portions  65   c  are disposed closer to the electrode connection portions  65   b  than the fourth fuse portions  65   f  is. 
         [0187]    A width D4 of each of the fourth fuse portions  65   f  is greater than a width D1 of each of the first fuse portions  65   c , and the width D4 of each of the fourth fuse portion  65   f  is less than two times the width D1 of each of the first fuse portions  65   c.    
         [0188]    A width D3 of the third fuse portion  65   e  (e.g., a width of a portion of the third fuse portion  65   e ) is less than the width D1 of each of the first fuse portions  65   c.    
         [0189]    Accordingly, the third fuse portion  65   e  is melted faster than the first fuse portions  65   c  when an overcurrent flows. 
         [0190]    When an internal short-circuit occurs in one of the electrode assemblies  10 , the short-circuit current flows from the other electrode assemblies  10  to the short-circuited electrode assembly  10 . 
         [0191]    The short-circuit current flows through the first fuse portions  65   c  and the electrode connection portions  65   b , and the first fuse portions  65   c  are melted when the short-circuit current flows. 
         [0192]    However, when the first fuse portions  65   c  are not completely melted, the current flows through the third fuse portion  65   e , and in this case, the third fuse portion  65   e  is melted. 
         [0193]    Moreover, the short-circuit current flows through the fourth fuse portions  631  after the third fuse portion  65   e  is melted, and the fourth fuse portions  65   f  are melted as a result. 
         [0194]    Once the third fuse portion  65   e  melts, each of the fourth fuse portions  65   f  become coupled to only two of the first fuse portions  65   c , and two times more current flows through the fourth fuse portions  65   f  than through each of the first fuse portions  65   c.    
         [0195]    Thus, the fourth fuse portions  651  may be easily melted, thereby complementing the first fuse portions  65   c  even when the fourth fuse portions  65   f  are formed larger (e.g., thicker) than the first fuse portions  65   c.    
         [0196]      FIG. 11  is a perspective view of a first current collecting member according to a fifth example embodiment of the present invention. 
         [0197]    Referring to  FIG. 11 , because a rechargeable battery according to the present example embodiment has the same or substantially the same structure as the first example embodiment described above, except for a structure of a first current collecting member, a repeated description of the structure may be omitted. 
         [0198]    A first current collecting member  67  includes a terminal connection portion  67   a  coupled to (e.g. bonded to) the connecting terminal  25  and electrode connection portions  67   b  extending from the terminal connection portion  67   a  towards the bottom of the case  26 . 
         [0199]    The terminal connection portion  67   a  has a quadrangular plate shape and is coupled to (e.g., fixed to) the bottom of the connecting terminal  25  by, for example, welding. 
         [0200]    A fastening opening  67   d  (e.g,. a fastening hole) is formed in the terminal connection portion  67   a , and the terminal connection portion  67   a  is welded to the connecting terminal  25  while the protrusion formed at the bottom of the connecting terminal  25  is inserted into (e.g., fitted into) the fastening opening  67   d.    
         [0201]    Two electrode assemblies  10  are disposed in parallel with each other in the case  26 , and the first current collecting member  67  is provided with two electrode connection portions  67   b.    
         [0202]    The electrode connection portions  67   b  are bent from first fuse portions  67   c  to be coupled to (e.g., bonded to) the positive electrode uncoated region  11   a  while being disposed in parallel therewith. 
         [0203]    The electrode connection portions  67   b  are respectively coupled to (e.g., bonded to) the positive electrode uncoated regions  11   a  of the different electrode assemblies  10  by, for example, welding. 
         [0204]    The first fuse portions  67   c  are formed between the electrode connection portions  67   b  and the terminal connection portion  67   a  such that they are melted faster than respective peripheral regions when an overcurrent flows. 
         [0205]    The first fuse portions  67   c  are bent from the terminal connection portion  67   a  to protrude towards the bottom of the case  26 . 
         [0206]    The two first fuse portions  67   c  are formed at the terminal connection portion  67   a  and are made of a material having a lower melting point than the respective peripheral regions. 
         [0207]    While this invention has been described in connection with what is presently considered to be practical example embodiments, it is to be understood that the invention is not limited to the disclosed embodiments but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents. 
         [0208]    Description of Reference Symbols 
         [0000]    
       
         
               
               
             
               
             
               
               
             
           
               
                   
               
             
             
               
                 101: rechargeable battery 
                 10: electrode assembly 
               
               
                 11: positive electrode (first 
                 11a: positive electrode uncoated region 
               
               
                 electrode) 
               
               
                 12: negative electrode (second 
                 12a: negative electrode uncoated 
               
               
                 electrode) 
                 region 
               
               
                 13: separator 
                 21: first terminal 
               
               
                 22: second terminal 
                 25: connection terminal 
               
               
                 26: case 
                 30: cap assembly 
               
               
                 31: cap plate 
                 32: electrolyte injection opening 
               
               
                 34: vent opening 
                 37: short-circuit opening 
               
               
                 38: sealing cap 
                 39: vent plate 
               
             
          
           
               
                 41, 61, 63, 65, 67: first current collecting member 
               
               
                 41a, 42a, 61a, 62a, 63a, 65a, 67a: terminal connection portion 
               
               
                 41b, 42b, 61b, 62b, 63b, 65b, 67b: electrode connection portion 
               
               
                 41c, 42c, 61c, 62c, 63c, 65c, 67c: first fuse portion 
               
               
                 41d, 42d, 61d, 62d, 63d, 65d, 67d: fastening opening 
               
               
                 42: second current collecting member 
               
               
                 43: lower insulation member 
               
             
          
           
               
                 45: lower insulation member 
                 54: upper insulation member 
               
               
                 55: sealing gasket 
                 56: short-circuit member 
               
               
                 58: connection member 
                 59: sealing gasket 
               
               
                 61e, 62e: second fuse portion 
                 63e, 65e: third fuse portion 
               
               
                 63f, 65f: fourth fuse portion