Abstract:
A battery module having improved interconnection members to connect rechargeable batteries together and to minimize an increase in a volume of the battery module includes: first and second rechargeable batteries, each having an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween, and a casing to contain the electrode assembly; a first interconnection member arranged on an upper side surface of the casing of the first rechargeable battery and electrically connected to the first electrode of the first rechargeable battery; and a second interconnection member arranged on a lower side surface of the casing of the second rechargeable battery and electrically connected to the second electrode of the second rechargeable battery, the second interconnection member being connected to the first interconnection member.

Description:
CLAIM OF PRIORITY 
       [0001]    This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C.§119 from an application for BATTERY MODULE earlier filed in the Korean Intellectual Property Office on 31 Jan. 2007 and there duly assigned Serial No. 10-2007-0010048. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is related to a battery module, and more particularly, the present invention is related to a battery module having interconnection members to connect rechargeable batteries with an improved structure. 
         [0004]    2. Description of the Related Art 
         [0005]    Generally, a battery module includes a few or several tens rechargeable batteries connected together. The rechargeable battery can be repeatedly charged and discharged because its chemical and electrical energy conversion is reversible. Recently, more and more mobile wireless electronic products are being developed, and a need exists for a rechargeable battery having an increased high energy density as its size and weight are reduced. 
         [0006]    Widely used batteries include a nickel-cadmium battery, a nickel-hydrogen battery, a lithium rechargeable battery, and the like. Particularly, the lithium rechargeable battery has an operating voltage of 3.6 V, which is triple that of the nickel-cadmium battery or the nickel-hydrogen battery, and also has a high energy density per unit weight. Therefore, the lithium rechargeable battery is being rapidly popularized as a power source for mobile electronic devices. Such a lithium rechargeable battery can be classified into a lithium ion rechargeable battery, a lithium ion polymer battery, and a lithium polymer battery. 
         [0007]    A typical rechargeable battery includes an electrode assembly having a positive electrode, a negative electrode, and a separator interposed therebetween, a casing providing a space for containing the electrode assembly, and a cap assembly combined with the casing to seal the electrode assembly. The rechargeable battery may be manufactured in a variety of shapes such as cylindrical, rectangular, and pouch types depending on the shapes of the electrode assembly and the casing. 
         [0008]    The battery module having a plurality of rechargeable batteries having the aforementioned structure and connected together is being widely used as a power source for driving motors of portable miniaturized electronic devices, such as mobile phones, personal computers, camcorders, and hybrid electric vehicles. 
         [0009]    The rechargeable batteries forming the battery module are connected together by interconnection members. The interconnection members are disposed at side ends of the rechargeable batteries so as to electrically connect adjacent rechargeable batteries together. Each rechargeable battery includes an element protruding from the side end in order to form the interconnection member, and this element is used to stably fix the interconnection member. 
         [0010]    However, the elements disposed at the side end of each rechargeable battery cause an increase in a length of the rechargeable battery, and this also causes an increase in a volume of the battery module. Therefore, for a compact construction of the battery module, there is a need for an improvement in the configuration of the interconnection members for connecting adjacent rechargeable batteries and components for fixing the interconnection members to the rechargeable batteries. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention provides a battery module having improving interconnection members to connect rechargeable batteries together and elements for fixing the interconnection members to the rechargeable battery and minimizing an increase in a volume of the battery module.  100101  According to an aspect of the present invention, a battery module is provided including: first and second rechargeable batteries, each having an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween, and a casing to contain the electrode assembly; a first interconnection member arranged on an upper side surface of the casing of the first rechargeable battery and electrically connected to the first electrode of the first rechargeable battery; and a second interconnection member arranged on a lower side surface of the casing of the second rechargeable battery and electrically connected to the second electrode of the second rechargeable battery, the second interconnection member being connected to the first interconnection member. 
         [0012]    The battery module preferably further includes an insulating member arranged between the upper side surface of the casing of the first rechargeable battery and the first interconnection member to insulate the first interconnection member from the casing of the first rechargeable battery. 
         [0013]    The first interconnection member preferably includes: a first cover including a body portion to cover the insulating member and an engaged portion connected to the body portion and electrically connected to the first electrode of the first rechargeable battery; and a first elongated portion having a side portion attached to the first cover and having another side portion connected to the second interconnection member. 
         [0014]    The second interconnection member preferably includes: a second cover to cover a lower side surface of the second rechargeable battery and electrically connected to the second electrode of the second rechargeable battery; and a second elongated portion having a side portion attached to the second cover and having another side portion connected to the first elongated portion. 
         [0015]    The battery module preferably further includes a bolt and mating nut to connect the first and second elongated portions together. 
         [0016]    The first and second elongated portions preferably further include through-holes into which the bolt is inserted, the through-holes penetrating the first and second elongated portions in a direction of a length of the first and second rechargeable batteries. 
         [0017]    The first and second elongated portions preferably alternatively further include through-holes into which the bolt is inserted, the through-holes penetrating the first and second elongated portions in a direction crossing a length of the first and second rechargeable batteries. 
         [0018]    The first and second elongated portions are preferably alternatively welded together. 
         [0019]    The battery module preferably further includes a hinge mechanism to connect the first and second elongated portions together, the hinge mechanism having a hinge angle preferably in a range of from 10° to 180°. 
         [0020]    An upper surface of the casing of the first rechargeable battery and a lower surface of the casing of the second rechargeable battery preferably face the same direction, and the first and second rechargeable batteries are preferably arranged in parallel. 
         [0021]    The first and second rechargeable batteries preferably respectively include first and second cylindrical rechargeable batteries. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    A more complete appreciation of the present invention and many of the attendant advantages thereof, will be readily apparent as the present invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
           [0023]      FIG. 1  is an exploded perspective view of a battery module according to a first embodiment of the present invention; 
           [0024]      FIG. 2  is a view of a first rechargeable battery connected to a first interconnection member of  FIG. 1 ; 
           [0025]      FIG. 3  is a view of a second rechargeable battery connected to a second interconnection member of  FIG. 1 ; 
           [0026]      FIG. 4  is a top plan view of a battery module according to a second embodiment of the present invention; 
           [0027]      FIG. 5  is a perspective view of a battery module according to a third embodiment of the present invention; and 
           [0028]      FIG. 6  is a top plan view of a battery module according to a fourth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Hereinafter, exemplary embodiments of the present invention are described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein, but may be embodied in various forms. Elements that do not correspond to the present invention have not been described in order to provide a simplified description for the present invention in association with the drawings. Like reference numerals denote like elements throughout the entire specification. Also, elements already well known in the art have not been described in detail. 
         [0030]      FIG. 1  is an exploded perspective view of a battery module  100  according to a first embodiment of the present invention. The battery module  100  according to the first embodiment of the invention includes first and second lithium ion rechargeable batteries  105  and  107 . The configuration of  FIG. 1  is provided to explain a principle of the present invention. The present invention is not limited to lithium ion rechargeable batteries. In addition, the battery module according to the present invention may include more than two rechargeable batteries, and such a configuration is also included in the scope of the present invention. 
         [0031]    As shown in  FIG. 1 , the battery module  100  includes the first and second rechargeable batteries  105  and  107  respectively having an electrode assembly  110 , a casing  120 , and a cap assembly  140 , an insulating member  129 , a first interconnection member  160 , and a second interconnection member  170 . 
         [0032]    Since the first and second rechargeable batteries  105  and  107  have the same structure in the current embodiment, the features of the first and second rechargeable batteries  105  and  107  are described below based on the first rechargeable battery  105 . 
         [0033]    The electrode assembly  110  includes a first electrode  114  (a positive electrode) having a charge collector where positive activation materials are attached, a second electrode  112  (a negative electrode) having a charge collector where negative activation materials are attached, and a separator  113  interposed between the positive and negative electrodes  114  and  112  for preventing a short circuit therebetween. 
         [0034]    More specifically, the negative electrode  112  is manufactured by coating a slurry type activation material layer obtained by mixing a negative activation material power, a negative binder, a bond, and the like on a charge collector such as a copper plate. In addition, the negative tap  132  is connected to the negative electrode  112  and makes contact with an internal bottom surface of the casing  120 . As a result, the casing  120  can function as a negative terminal of the first rechargeable battery  105 . Needless to say, it would be apparent to those skilled in the art that a negative charge collector (not shown) instead of the negative tap  132  may be connected to the negative electrode  112 . 
         [0035]    The positive electrode  114  is manufactured by uniformly coating a slurry type activation material layer obtained by mixing a positive activation material power, a positive binder, a positive conductive additive, and the like on a charge collector such as an aluminum plate. A positive tap  134  is connected to the positive electrode  114 , extended away from the positive electrode  114 , and then connected to a safety vent  142  of the cap assembly  140 . Needless to say, a positive charge collector (not shown) instead of the positive tap  134  may be connected to the positive electrode  114 . In this case, a lead tap (not shown) of the positive charge collector is connected to the cap assembly  140 . 
         [0036]    The separator  113  separates the positive and negative electrodes  112  and  114  from each other, and provides a circulation path for the lithium ions. The separator  113  may be a single layered film formed of polyethylene, polypropylene, or polyvinylidene fluoride, a multi-layered film having two or more layers formed of polyethylene, polypropylene, or polyvinylidene fluoride, or a mixed multi-layered film such as a polyethylene/polypropylene double layered separator, a polyethylene/polypropylene/polyethylene triple layered film, and a polypropylene/polyethylene/polypropylene triple layered separator. 
         [0037]    This electrode assembly  110  may be obtained by sequentially stacking the negative electrode  112 , the separator  113 , and the positive electrode  114 , combining a center rod (not show) with the end of the stack, and winding them in a cylindrical shape. The resultant electrode assembly  110  may be inserted into the casing  120 , which will be described later, and then, the center rod removed from the electrode assembly  110 . A vacant space formed by the removal of the center rod may be filled with a center pin (not shown). 
         [0038]    Upper and lower insulation plates  138  and  136  are respectively installed on upper and lower sides of the aforementioned electrode assembly  110  in order to prevent an unnecessary electrical short between the electrode assembly  110  and the casing  120 . 
         [0039]    The casing  120  includes an internal space for containing the electrode assembly  110  in a cylindrical shape, and is formed of a conductive metallic material, such as aluminum, aluminum alloy, and steel plated with nickel. The casing  120  has an open top surface, into which the electrode assembly  110  can be inserted. 
         [0040]    The opened top surface of the casing  120  is combined with the cap assembly  140  to seal the casing  120 . In the process of combining the casing  120  and the cap assembly  140 , the casing  120  is provided with a bead portion  123  and a crimped portion  125 . 
         [0041]    The internal space of the sealed casing  120  is filled with electrolyte (not shown), which allows the lithium ions generated by an electrochemical reaction to move between the positive and negative electrodes  112  and  114  during the charge/discharge operations. 
         [0042]    The cap assembly  140  includes an electrode cap  143 , a positive temperature coefficient element  141 , a safety vent  142 , an electrode cap  143 , and a gasket  144 . 
         [0043]    The gasket  144  covers side surfaces of the conductive electrode cap  143 , the positive temperature coefficient element  141 , and the safety vent  142  and is disposed between them and the casing  120  to insulate them from the casing  120 . 
         [0044]    The safety vent  142  has a lower surface where the positive tap  134  extracted from the positive electrode  114  is attached using a bonding process, such as a welding. The safety vent  142  is upwardly switched to cut off electrical connection with the positive electrode  114  when an internal pressure of the first rechargeable battery  105  exceeds a predetermined value. Although the safety vent  142  and the positive tap  134  are directly connected together in the current embodiment, it would be apparent to those skilled in the art that an insulation member (not shown) and a cap plate (not shown) may be further sequentially stacked under the safety vent  142 , and the positive tap  134  connected to the cap plate. 
         [0045]    The positive temperature coefficient element  141  is connected to an upper portion of the safety vent  142 . An electrical resistance of the positive temperature coefficient element  141  increases to a nearly infinite level when its temperature exceeds a predetermined level. Therefore, it can be used to stop a charge/discharge current flow when the temperature of the first rechargeable battery  105  increases beyond a predetermined level. When the temperature of the first rechargeable battery  105  lowers to below a predetermined level, the electrical resistance of the positive temperature coefficient element  141  is reduced again. Accordingly, the functions of the first rechargeable battery  105  can be recovered. 
         [0046]    The electrode cap  143  is connected to an upper portion of the positive temperature coefficient element  141  and serves as a positive terminal to externally supply the current. The side surface of the electrode cap  143  is provided with a degassing hole  143   a  which allows an internal gas of the first rechargeable battery  105  to be ventilated when the safety vent  142  is opened. 
         [0047]    The insulating material  129  is formed on an upper side surface of the first rechargeable battery  105  having the aforementioned structure. The insulating material  129  has functions of maintaining insulation between the electrodes and absorbing vibration. In addition, the insulating material  129  cuts off electrical connection between the first interconnection member  160  and the casing  120 . Although the second rechargeable battery  107  is not provided with an insulating member  129  in the current embodiment, it would be apparent to those skilled in the art that the insulating member may be provided with the second rechargeable battery  107 . 
         [0048]    The first interconnection member  160  covers a side surface of the insulating member  129  provided to the first rechargeable battery  105  and is electrically connected to the electrode cap  143 . The second interconnection member  170  is formed to cover a lower side surface of the casing  120  of the second rechargeable battery  107 . The second interconnection member  170  is combined with the first interconnection member  160  by a bolt  182  and a nut  184 , so that the first and second rechargeable batteries  105  and  107  are electrically connected with each other. 
         [0049]      FIG. 2  is a view of the first rechargeable battery  105  connected to the first interconnection member  160  of  FIG. 1 . As shown in  FIG. 2 , the first interconnection member  160  includes a first cover  165  and a first elongated portion  166 . 
         [0050]    The first cover  165  includes a body portion  162  for covering the insulating member  129  and an engaged portion  164  that is combined with the body portion  162  and electrically connected to the electrode cap  143 . 
         [0051]    The first elongated portion  166  protrudes from the body portion  162  and is provided with a first through-hole  166   a  into which the bolt  182  (see  FIG. 1 ) is inserted. The first through-hole  166   a  is formed in the first elongated portion  166  in a direction of a length of the first rechargeable battery  105 . The first elongated portion  166  is engaged with a second elongated portion  176  (see  FIG. 3 ) which will be described later, and accordingly, the first and second rechargeable battery  105  and  107  can be electrically connected to each other. 
         [0052]    The first interconnection member  160  having the aforementioned construction is electrically connected to the positive electrode of the first rechargeable battery  105 . More specifically, since the engaged portion  164  of the first cover  165  is fixed to the electrode cap  143  having a function of a positive terminal, the first interconnection member  160  can be electrically connected to a positive electrode of the first rechargeable battery  105 . The body portion  162  of the first cover  165  is disposed to cover the side surface of the insulating member  129 , so that the first interconnection member  160  is insulated from the casing  120  having a function of a negative terminal. 
         [0053]      FIG. 3  is a view of the second rechargeable battery  107  connected to the second interconnection member  170  of  FIG. 1 . As shown in  FIG. 3 , the second interconnection member  170  includes a second cover  175  and a second elongated portion  176 . 
         [0054]    The second cover  175  is formed in a shape of an open-ended cylinder disposed to cover a lower side surface of the casing  120  of the second rechargeable battery  107 . As described above, the second cover  175  is directly connected to the casing  120  having a function of a negative terminal of the second rechargeable battery  107 , so that the second interconnection member  170  can be electrically connected to a negative electrode of the second rechargeable battery  107 . 
         [0055]    A side portion of the second elongated portion  176  is fixed to the second cover  175 , and the other side portion is combined with the first elongated portion  166  (see  FIG. 2 ). The second elongated portion  176  is provided with a second through-hole  176   a  into which the bolt  182  (see  FIG. 1 ) is inserted. The second through-hole  176   a  is formed in the second elongated portion  176  in a direction of a length of the second rechargeable battery  107  and disposed to be aligned with the first through-hole  166   a  of the first elongated portion  166 . 
         [0056]    As described above, the second elongated portion  176  is combined with the first elongated portion  166  of the first rechargeable battery  105 , so that the first and second rechargeable batteries  105  and  107  are electrically connected to each other. In the current embodiment, the second and first elongated portions  176  and  166  are combined by the bolt  182  penetrating the second and first through-holes  176   a  and  166   a  and the nut  184  (see  FIG. 1 ) mated with the bolt  184  (see  FIG. 1 ). 
         [0057]    In the current embodiment, according to the aforementioned constructions, although the first and second rechargeable batteries  105  and  107  are connected to each other, the length of the rechargeable batteries is not increased due to the improved first and second interconnection members  160  and  170 , and this means that a volume of the battery module  100  having a plurality of the rechargeable batteries does not increase. 
         [0058]    As shown in  FIG. 4 , a first through-hole formed in a first elongated portion  266  and a second through-hole formed in a second elongated portion  277  maybe formed in a direction crossing the length of the first and second rechargeable batteries  105  and  107 . More specifically, according to a battery module  200  in the second embodiment, a bolt  182  penetrates the first and second through-holes in the direction crossing the length of the first and second rechargeable batteries  105  and  107 , and a nut  184  is mated with the bolt  182 , so that first and second interconnection members are connected. 
         [0059]    In addition, as shown in  FIG. 5 , first and second interconnection members  360  and  370  are combined by performing a resistance welding or a laser welding. More specifically, according to a battery module  300  in the third embodiment, a first elongated portion  366  of the first interconnection member  360  is combined with a second elongated portion  377  of the second interconnection member  370  by performing a welding, so that the first and second rechargeable batteries  105  and  107  can be electrically connected. 
         [0060]      FIG. 6  is a top plan view showing a battery module  400  according to a fourth embodiment of the present invention. Referring to  FIG. 6 , first and second interconnection members  460  and  470  are combined by a bolt  182  and a nut (not shown). In addition, an included angle θ between a center line of the first elongated portion  466  in a length direction and a center line of the second elongated portion  477  in a length direction is formed to be in a range of from 10° to 180°. According to the fourth embodiment, the included angle θ is controlled so as to freely control a distance s between the first and second rechargeable batteries  105  and  107 . In other words, according to a size of a device applying the battery module  400 , the distance between the first and second rechargeable batteries  105  and  107  can be controlled to correspond to the size, so that an adaptability of the battery module  400  for the device applying the battery module  400  can increase. 
         [0061]    Other technical features may be similarly applied as in the aforementioned first embodiment. 
         [0062]    As described above, according to the embodiments of the present invention, due to the improved first and second interconnection members, although a plurality of the rechargeable batteries are connected together, the length of the rechargeable batteries is not increased. 
         [0063]    In addition, according to the embodiments of the present invention, a distance between adjacent rechargeable batteries can be controlled so that the entire size of the battery module can be freely determined. In other words, there is an advantage in that an adaptability of the battery module for a device applying the battery module increases. 
         [0064]    Although the exemplary embodiments of the present invention have been described, the present invention is not limited to these embodiments, but may be modified in various ways without departing from the scope of the appended claims.