Patent Publication Number: US-2010124674-A1

Title: Battery pack

Description:
BACKGROUND 
     1. Field 
     Embodiments relate to a battery pack. 
     2. Description of the Related Art 
     In a typical battery pack, a bare cell may be electrically connected to a protective circuit module. The bare cell may be produced by providing an electrode assembly and an electrolyte in a can and sealing the can. The bare cell may be electrically charged and discharged by, e.g., chemical reactions. The protective circuit module may include, e.g., a printed circuit board and electrical components mounted on the printed circuit board. The electrical components may include, e.g., integrated circuits, charge/discharge switches and passive devices. The protective circuit module may protect the bare cell from, e.g., overcharge, overdischarge and overcurrent, while controlling the bare cell. The protective circuit module may also prevent deterioration of performance of the battery pack. 
     Battery packs may be classified into horizontal and vertical mounting types, depending on the mounting position of the corresponding protective circuit modules. A horizontal mounting type battery pack may have a structure in which a protective circuit module is mounted on a side surface of a bare cell. In the horizontal mounting type battery pack, a fixing member may be disposed between the side surface of the bare cell and the protective circuit module to stably secure and hold the protective circuit module on the bare cell. 
     SUMMARY 
     Embodiments are therefore directed to a battery pack, which substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art. 
     It is therefore a feature of an embodiment to provide a battery pack having a simplified assembly procedure and reduced production costs. 
     At least one of the above and other features and advantages may be realized by providing a battery pack including a bare cell, a protective circuit module electrically connected to the bare cell, and a case assembly overlying the bare cell and protective circuit module, the case assembly including a cover case and a fixing member; the cover case and the fixing member of the case assembly both being integral with each other. 
     The fixing member may have a first side surface, a second side surface opposite to the first side surface, a third side surface and a fourth side surface, the first side surface and the second side surface may each have a first end and a second end opposite to the first end, the third side surface may connect the first ends of the first side surface and the second side surface, and the fourth side surface may connect the second ends of the first side surface and the second side surface. 
     The bare cell may have a short side wall having a shape, and the first side surface of the fixing member may have a shape corresponding to the shape of the short side wall of the bare cell and overlies the short side wall of the bare cell. 
     The second side surface of the fixing member may be substantially planar and may contact the protective circuit module. 
     The third and fourth side surfaces of the fixing member may be asymmetric. 
     The cover case may include an upper cover and first and second side covers at ends of the upper cover, the upper cover may have a first sidewall, and the third side surface of the fixing member may be connected to the first sidewall of the upper cover through a connecting portion. 
     The upper cover may have a second sidewall opposite to the first sidewall, at least one coupling hole may be disposed in the second sidewall, and the fourth side surface of the fixing member may have at least one coupling protrusion corresponding to the coupling hole. 
     Each coupling protrusion may be coupled to one of the coupling holes. 
     The connecting portion may continuously connect the cover case and the fixing member. 
     The cover case and the fixing member may be bent about the connecting portion. 
     The connecting portion may discontinuously connect the cover case and the fixing member. 
     The connecting portion may include at least one hinge hole. 
     The cover case and the fixing member may be bent about the connecting portion. 
     The cover case and the fixing member may be of one piece. 
     At least one of the above and other features and advantages may also be realized by providing a battery pack including a bare cell including a negative terminal on an upper surface thereof, a protective circuit module disposed on the upper surface of the bare cell and electrically connected to the bare cell, and a case assembly overlying the bare cell and protective circuit module, the case assembly including a cover case and a fixing member; the cover case and the fixing member of the case assembly both being integral with each other. 
     The cover case may include a connecting portion integral with and between the cover case and fixing member. 
     The cover case and the fixing member may be bent about the connecting portion. 
     The fixing member may be substantially planar and may have a terminal recess at a central portion thereof. 
     The negative terminal may penetrate the terminal recess. 
     The fixing member may be spaced apart from the bare cell. 
     The cover case and the fixing member may be of one piece. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings, in which: 
         FIG. 1A  illustrates an exploded perspective view of a battery pack according to an embodiment; 
         FIG. 1B  illustrates a partially assembled perspective view of the battery pack of  FIG. 1A ; 
         FIG. 1C  illustrates an assembled perspective view of the battery pack of  FIG. 1A ; 
         FIG. 1D  illustrates a partial cross-sectional view taken along line A-A of  FIG. 1C ; 
         FIGS. 2A and 2B  illustrate perspective views of a case assembly of the battery pack of  FIG. 1A  as viewed from different directions; 
         FIG. 2C  illustrates a pre-assembled perspective view of the case assembly of  FIGS. 2A and 2B ; 
         FIG. 3  illustrates a perspective view of a case assembly of a battery pack according to another embodiment; and 
         FIG. 4  illustrates an exploded perspective view of a battery pack according to yet another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Korean Patent Application No. 10-2008-0115301, filed on Nov. 19, 2008, in the Korean Intellectual Property Office, is incorporated by reference herein in its entirety. 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout. 
     Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the embodiments by referring to the figures. 
       FIG. 1A  illustrates an exploded perspective view of a battery pack according to an embodiment.  FIG. 1B  illustrates a partially assembled perspective view of the battery pack of  FIG. 1A .  FIG. 1C  illustrates an assembled perspective view of the battery pack of  FIG. 1A .  FIG. 1D  illustrates a partial cross-sectional view taken along line A-A of  FIG. 1C .  FIGS. 2A and 2B  illustrate perspective views of a case assembly of the battery pack of  FIG. 1A  as viewed from different directions.  FIG. 2C  illustrates a pre-assembled perspective view of the case assembly. 
     Referring to  FIGS. 1A through 1D  and  FIGS. 2A through 2C , the battery pack  100  may include a bare cell  110 , a protective circuit module  120  and a case assembly  130 . The battery pack  100  may further include a label  140 . The case assembly  130  may include a cover case  131  and a fixing member  133 , which may be integrally formed with each other. Due to this structure, the battery pack  100  may be fabricated in a simple manner at low cost. 
     The bare cell  110  may be a can-type battery having a positive electrode  111  and a negative terminal  112 . The bare cell  110  may have a structure in which an electrode assembly (not shown) and an electrolyte (not shown) are accommodated in a metal can  113  having an open end. The can  113  may then be sealed with a cap assembly  114 . The positive electrode  111  of the electrode assembly may be electrically connected to the can  113 . The negative terminal  112  of the electrode assembly may be insulated from the cap assembly  114  and the can  113 . 
     Although not shown, the electrode assembly may include a positive electrode plate, a negative electrode plate and a separator. The separator may be interposed between the positive and negative electrode plates to insulate the two electrode plates. That is, the electrode assembly may be a laminate of the positive electrode plate, the negative electrode plate and the separator. The laminate may be wound in the form of a ‘jelly-roll’ to obtain a structure with, e.g., high capacitance. 
     The can  113  for use in a prismatic secondary battery may be made of a metal and may have a substantially hexahedral shape. The can  113  may have an opening at an end thereof. The can  113  may be produced by any suitable process, e.g., deep drawing. The can  113  may have a first surface  113   a  in contact with the fixing member  133  and a second surface  113   b  opposite to the first surface  113   a . Third and fourth surfaces  113   c  and  113   d  may connect to the first and second surfaces  113   a  and  113   b  to form long side walls. The can  113  may also have a fifth surface  113   e  to close one of two ends defined by the first, second, third and fourth surfaces  113   a ,  113   b ,  113   c  and  113   d . The other end of the can  113  may be closed by the cap assembly  114 . The can  113  may be made of a lightweight conductive metal, e.g., aluminum (Al) or aluminum alloys. The conductivity of the metallic material may allow the can  113  to serve as a terminal. The can  113  may accommodate the electrode assembly and the electrolyte. 
     As mentioned above, the cap assembly  114  may close the opening of the can  113 . The cap assembly  114  may include a metal cap plate  114   a  and an insulating gasket (not shown) insulating the negative terminal  112  from the cap plate  114   a . The cap plate  114   a  and the can  113  may be electrically connected to the positive electrode  111  of the electrode assembly. The negative terminal  112  may be electrically connected to the negative electrode of the electrode assembly. The cap assembly  114  may further include an insulating plate (not shown) under the cap plate  114   a , a terminal plate (not shown) under the insulating plate and an insulating case (not shown) under the terminal plate. 
     The protective circuit module  120  may be electrically connected to the bare cell  110 . The protective circuit module  120  may include an insulating substrate  121 , charge/discharge terminals  122  and lead tabs  123 . The lead tabs  123  may include a first lead tab  123   a  and a second lead tab  123   b . A positive (+) electrode of the protective circuit module  120  may be electrically connected to the positive electrode  111  of the bare cell  110  through the first lead tab  123   a . A negative (−) electrode of the protective circuit module  120  may be electrically connected to the negative terminal  112  of the bare cell  110  through the second lead tab  123   b . However, polarities of the positive electrode  111  and the negative terminal  112  of the bare cell  110  may be reversed. 
     The insulating substrate  121  may include a polymer resin, e.g., Bakelite, or an epoxy resin. The insulating substrate  121  may have a plurality of conductive metal patterns (not shown) printed on a lower surface thereof. That is, the insulating substrate  121  may be a printed circuit board (PCB). Active devices (not shown), e.g., a charge/discharge switching device and/or a field effect transistor, may be coupled to the metal patterns. A passive device, e.g., a resistor, a capacitor and/or an inductor may also be coupled to the metal patterns. The passive devices may be electrically connected to the active devices to, e.g., set voltages and currents applied to the active devices, thus allowing the active devices to be operated in a balanced mode. 
     The protective circuit module  120  may further include safety means to ensure stability of the battery against dangers, e.g., explosion and fire, during charging and discharging of the bare cell  110 . The protective circuit module  120  may include a safety element (not shown), e.g., a thermistor whose electrical resistance varies in response to a temperature change when the internal temperature of the bare cell  110  increases and/or a positive temperature coefficient (PTC) element to block a flow of current when the temperature of the bare cell  110  increases above a predetermined value. 
     The charge/discharge terminals  122  may be disposed on an upper surface of the insulating substrate  121 . The charge/discharge terminals  122  may be electrically connected to the metal patterns. The charge/discharge terminals  122  may include a positive terminal  122   a , an auxiliary terminal  122   b  and a negative terminal  122   c . The charge/discharge terminals  122  may be terminals through which the bare cell  110  is electrically connected to an external system (not shown). 
     The first and second lead tabs  123   a  and  123   b  may be electrically connected to the positive electrode  111  and the negative terminal  112  of the bare cell  110 , respectively. For the electrical connection, central portions of the first and second lead tabs  123   a  and  123   b  may be bent. The lead tabs  123  may electrically connect the bare cell  110  and the protective circuit module  120 . 
     The case assembly  130  may be a, e.g., plastic, case in which the cover case  131  is separated from the fixing member  133  by a connecting portion  135 . The cover case  131  may be integrated with the fixing member  133  through the connecting portion  135 . The case assembly  130  may be made in one piece by, e.g., injection molding, of a resin, e.g., polycarbonate. A typical cover case and fixing member are individually made in different molds and assembled to each other to constitute a pack. According to the embodiments, only one mold may be needed to produce the case assembly  130  including the integrally formed cover case  131  and fixing member  133 . The use of one mold beneficially simplifies the fabrication procedure of the battery pack  100  and advantageously reduces the fabrication cost of the battery pack  100 . The case assembly  130  may i) bring the bare cell  110  into close contact with the protective circuit module  120 , ii) protect the protective circuit module  120  from, e.g., external impacts, and iii) prevent shorts between the bare cell  110  and the protective circuit module  120 . 
     The cover case  131  may be connected to the fixing member  133  through the connecting portion  135 . The cover case  131  may include an upper cover  131   a , a first side cover  131   b  and a second side cover  131   c . The cover case  131  may include one or more coupling holes  131   d  into which one or more coupling protrusions  133   e  of the fixing member  133  may be fitted. The cover case  131  may include charge/discharge terminal holes  131   e  through which the charge/discharge terminals  122  are exposed to the outside. The upper cover  131   a  may surround an upper portion of the protective circuit module  120 . The charge/discharge terminal holes  131   e  may penetrate the upper cover  131   a . The charge/discharge terminals  122  on the upper surface of the protective circuit module  120  may be exposed to the outside through the charge/discharge terminal holes  131   e . The first and second side covers  131   b  and  131   c  may be connected to ends of the upper cover  131   a  and may cover surfaces of the bare cell  110  on which the first and second lead tabs  123   a  and  123   b  are positioned. The first and second side covers  131   b  and  131   c  may prevent contact and shorts between the, e.g., metallic, first and second lead tabs  123   a  and  123   b  and an external conductor (not shown). 
     The fixing member  133  may have a relatively wide first side surface  133   a , a second side surface  133   b  opposite to the first side surface, a relatively narrow third side surface  133   c  and a fourth side surface  133   d  opposite to the third side surface. The first and second side surfaces  133   a  and  133   b  may overlie the first surface  113   a  of the can  113  and contact a lower surface of the protective circuit module  120 , respectively. The third side surface  133   c  may be connected to the connecting portion  135 , and the fourth side surface  133   d  may include the coupling protrusions  133   e . The third and fourth side surfaces  133   c  and  133   d  may be asymmetric. That is, the distance between opposite ends of the first and second side surfaces  133   a  and  133   b  at the third side surface  133   c  may be different from the distance between other opposite ends of the first and second side surfaces  133   a  and  133   b  at the fourth side surface  133   d . This is because opposite long side walls of the cover case  131  may be structurally asymmetric. After pre-assembly of the case assembly  130 , the third and fourth side surfaces  133   c  and  133   d  may be in a horizontal position due to their asymmetry. The fixing member  133  may secure and hold the protective circuit module  120  between the second side surface  133   b  and the upper cover  131   a.    
     The fixing member  133  may be connected to the cover case  131  through the connecting portion  135 . The connecting portion  135  may be defined as an area in which the third side surface  133   c  of the fixing member  133  is continuously connected to a long side wall of the upper cover  131   a  without interruption. 
     The first side surface  133   a  of the fixing member  133  may overlie a long side wall of the bare cell  110 . More specifically, the first side surface  133   a  of the fixing member  133  may overlie the first surface  113   a  of the can  113 . There is no restriction on the shapes of the first side surface  133   a  of the fixing member  133  and the first surface  113   a  of the can  113 . As illustrated in  FIG. 1D , the first side surface  133   a  of the fixing member  133  may be rounded in a concave manner and the first surface  113   a  of the can  113  may be rounded in a convex manner. Alternatively, the first surface  113   a  of the can  113  and the first side surface  133   a  of the fixing member  133  may be substantially planar. The second side surface  133   b  of the fixing member  133  is preferably substantially planar so as to be in close contact with the lower surface of the protective circuit module  120 . The coupling protrusions  133   e  of the fixing member  133  may be disposed on the fourth side surface  133   d  of the fixing member  133 . The coupling protrusions  133   e  may be disposed at positions corresponding to the coupling holes  131   d  in the upper cover  131   a . Upon assembly, the coupling protrusions  133   e  may be press-fitted into the coupling holes  131   d  in a one-to-one relationship. 
     A more detailed explanation of the coupling of the cover case  131  to the fixing member  133 , which may be integrally formed with one another, will be provided hereinafter. First, the protective circuit module  120  may be inserted within the upper cover  131   a  of the case assembly  130 . Then, the charge/discharge terminals  122  of the protective circuit module  120  may be correctly positioned such that the charge/discharge terminals  122  are exposed to the outside through the respective charge/discharge terminal holes  131   e . Next, the fixing member  133  may be bent about the connecting portion  135 , in which a long side wall of the upper cover  131   a  and the third side surface  133   c  of the fixing member  133  meet each other, toward the other long side wall of the upper cover  131   a . Then, the coupling protrusions  133   e  on the fourth side surface  133   d  of the fixing member  133  may be press-fitted into the coupling holes  131   d  in the other long side of the upper cover  131   a  to complete pre-assembly of the case assembly  130 . Thereafter, the case assembly  130  may be coupled to the bare cell  110 . As described above, the protective circuit module  120  may be mounted within the case assembly  130  before the case assembly  130  is coupled to the bare cell  110 , leading to a further improvement in operational efficiency. 
     An adhesive portion  139  may be disposed between the bare cell  110  and the fixing member  133  to enhance adhesion and bonding of the bare cell  110  to the fixing member  133 . Due to the case assembly  130  including the integrally formed cover case  131  and fixing member  133 , the overall fabrication procedure of the battery pack  100  may be effectively simplified. In addition, pre-assembly of the protective circuit module  120  and the case assembly  130  may prevent errors during assembly of the bare cell  110 , enabling efficient fabrication of the battery pack  100 . 
     Finally, the label  140  may surround the bare cell  110 . The label  140  may be adhered to the bare cell  110  and the case assembly  130  by means of an adhesive. Information, e.g., capacity and product number, about the battery pack  100  may be printed on an outer surface of the label  140 . 
     As described above, the case assembly  130  of the battery pack  100  may include the integrally formed cover case  131  and fixing member  133 . That is, the case assembly  130  may be made using one mold. Accordingly, the overall fabrication procedure of the battery pack  100  may be simplified, thus achieving improved productivity and efficiency. In addition, the battery pack  100  may be fabricated without the use of an additional mold for producing the fixing member  133 , resulting in a reduction in the fabrication cost of the battery pack  100 . 
     Hereinafter, an explanation will be given of a battery pack according to another embodiment.  FIG. 3  illustrates a perspective view of a case assembly  230  of the battery pack. The battery pack according to the present embodiment may have the same constituent elements as the battery pack  100  according to the previous embodiment except for the structure of the connecting portion, and repeated explanation of the same elements is omitted. Only differences between the embodiments will be explained below. 
     According to the present embodiment, the battery pack may include a bare cell  110 , a protective circuit module  120  and a case assembly  230 . Referring to  FIG. 3 , the case assembly  230  may include a cover case  231  and a fixing member  233 , which may be integrated with each other through a connecting portion  235 . In other words, the cover case  231 , fixing member  233  and connecting portion  235  may be integrally formed. The case assembly  230  may be made of the same material by the same process and may perform the same role as the case assembly  130 . The case assembly  230  may be a, e.g., plastic, case in which a cover case  231  is separated from the fixing member  233  by the connecting portion  235 . 
     The cover case  231  may be connected to the fixing member  233  through the connecting portion  235 . The cover case  231  may include an upper cover  231   a , a first side cover  231   b  and a second side cover  231   c . The cover case  231  may include charge/discharge terminal holes  231   e  through which the charge/discharge terminals  122  of the protective circuit module  120  are exposed to the outside. 
     The fixing member  233  may have a relatively wide first side surface  233   a , a second side surface  233   b  opposite to the first side surface  233   a , a relatively narrow third side surface  233   c  and a fourth side surface  233   d  opposite to the third side surface  233   c . The first and second side surfaces  233   a  and  233   b  may overlie the first surface  113   a  of the can  113  and contact the protective circuit module  120 , respectively. The third side surface  233   c  may be connected to the connecting portion  235 . The fourth side surface  233   d  may include one or more coupling protrusions (not shown), which may be press-fitted into one or more coupling holes (not shown) disposed on the upper cover  231   a  at positions corresponding to the coupling protrusions. The connecting portion  235  may include one or more hinge holes  235   a . The connecting portion  235  may extend discontinuously between the fixing member  233  and cover case  231  due to the hinge holes  235   a . The hinge holes  235   a  may allow the cover case  231  and the fixing member  235  to more easily bend about the connecting portion  235  when the protective circuit module  120  is mounted within the case assembly  230  (i.e. during pre-assembly). That is, the hinge holes  235   a  may enhance the flexibility of the connecting portion  235 . The number of the hinge holes  235   a  is not limited. It is preferred that two or more hinge holes  235   a  are arranged at regular intervals. As demonstrated above, the hinge holes  235   a  of the connecting portion  235  may further improve workability during the pre-assembly process for mounting the protective circuit module  120  within the case assembly  230 . 
     A battery pack  300  according to yet another embodiment will be explained below.  FIG. 4  illustrates an exploded perspective view of the battery pack  300 . The battery pack  300  may be a vertical mounting type, and may have the same constituent elements having the same functions and effects as the horizontal mounting type battery pack  100  described above, except for slight differences in the position and structure of the elements. Accordingly, the same reference numerals are given to the same components as the components of the previous embodiment; and repeated descriptions thereof are omitted. Only differences between the embodiments will be explained below. 
     Referring to  FIG. 4 , the vertical mounting type battery pack  300  may include a bare cell  100 , a protective circuit module  320  and a case assembly  330 . The protective circuit module  320  may include an insulating substrate  321 , charge/discharge terminals  322  and lead tabs  323 . The charge/discharge terminals  322  may include a positive terminal  322   a , an auxiliary terminal  322   b  and a negative terminal  322   c . The protective circuit module  320  may further include a welding hole  324 . The welding hole  324  may provide a passage for, e.g., resistance welding. Specifically, a resistance welding rod may be inserted through the welding hole  324  and may be used to weld a negative terminal  112  of the underlying bare cell  110  to a conductive plate (not shown) electrically connected to a secondary protective device (not shown). A positive electrode of the bare cell  110  may be connected to a positive (+) electrode of the protective circuit module  320  through one of the lead tabs  323  of the protective circuit module  320 . The protective circuit module  320  may be made of the same material by the same process and may perform the same role as the protective circuit module  120 , except for a slight difference in its position. 
     The case assembly  330  may include a cover case  331 , a fixing member  333  and a connecting portion  335 . The case assembly  330  may be constructed of, e.g., plastic, in which the cover case  331  is separated from the fixing member  333  by the connecting portion  335 . The cover case  331  may be integrated with the fixing member  333  through the connecting portion  335 . The case assembly  330  may be made of the same material by the same process and may perform the same role as the case assembly  130 . 
     The cover case  331  may be connected to the fixing member  333  through the connecting portion  335 . The cover case  331  may include charge/discharge terminal holes  331   e  through which the charge/discharge terminals  322  of the protective circuit module  320  are exposed to the outside. The cover case  331  may include one or more coupling holes (now shown) into which one or more coupling protrusions  333   e  of the fixing member  333  may be fitted. 
     The fixing member  333  may secure and hold the protective circuit module  320  in the case assembly  330 . The connecting portion  335  may be continuously connected to the fixing member  333 , in a similar fashion as the connecting portion  135  described above. Alternatively, the connecting portion  335  may be discontinuously connected to the fixing member  333 , in a similar fashion as the connecting portion  235  described above. 
     The battery pack  300  may have a structure in which the protective circuit module  320  overlies the negative terminal  112  of the bare cell  110 . Due to this structure, the fixing member  333  may have a terminal recess  333   b  corresponding to the welding hole  324  of the protective circuit module  320  at a central portion thereof so that the negative terminal  112  of the bare cell  110  penetrates the terminal recess  333   b . In a typical vertical mounting type battery pack, an insulating tape may be attached to an upper surface of a bare cell to prevent shorts between a protective circuit module and the bare cell. This step of applying the insulating tape may require additional labor and processing. In contrast, according to the present embodiment, the case assembly  330 , including the integrally formed cover case  331  and fixing member  333 , may enable pre-assembly of the protective circuit module  320 , thus eliminating the need for additional processing steps. It is preferred that the thickness of the fixing member  333  is smaller than that of the lead tabs  323 , thus allowing the bare cell  110  to be spaced apart from the protective circuit module  320 . The fixing member  333  may be planar and may have one or more coupling protrusions  333   e  on a sidewall thereof and opposite to the connecting portion  335 . Upon pre-assembly of the case assembly  330 , the coupling protrusions  333   e  may be press-fitted into coupling holes (not shown) of the cover case  331 . 
     Hereinafter, the assembly procedure of the battery pack  300  will be briefly explained. First, after the protective circuit module  320  is correctly positioned on the bare cell  110 , the lead tabs  323  may be coupled to the bare cell by, e.g., laser welding. The negative terminal  112  may be coupled to the protective circuit module  320  by, e.g., resistance welding. Next, the fixing member  333  of the case assembly  330  may be laterally inserted into a space defined by the bare cell  110  and the protective circuit module  320 . The negative terminal  112  may be disposed within the terminal recess  333   b  of the fixing member  333 . Next, the cover case  331  of the case assembly  330  may be coupled to the fixing member  333  to complete the fabrication of the battery pack  300 . 
     As described above, the case assembly  330  may include the integrally formed cover case  331  and the fixing member  333 . The case assembly  330  of the battery pack  300  may not be pre-assembled, unlike the case assembly  130  of the battery pack  100  described above. However, the fabrication procedure of the battery pack  300  may be simplified in a manner similar to that of the battery pack  100 , leading to an overall improvement in productivity and efficiency. 
     As is apparent from the above description, the battery packs of the embodiments may include a case assembly including an integrally formed cover case and fixing member. Since the case assembly may be made using one mold, the fabrication procedure of the battery packs may be simplified. This may lead to an improvement in productivity and efficiency. In addition, the battery packs of the embodiments may be fabricated at low cost. 
     A typical fixing member may be individually produced using an additional mold, which may increase production costs, eventually resulting in an increase in the overall fabrication cost of a battery pack. The use of the typical fixing member in the fabrication of the battery pack may involve additional steps, e.g., alignment of the fixing member in a correct position between the bare cell and the protective circuit module and coupling the fixing member to the bare cell and the protective circuit module. These additional steps may complicate the fabrication procedure of a battery pack, thereby lowering productivity and efficiency. 
     Exemplary embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.