Patent Publication Number: US-2015072178-A1

Title: Battery pack

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Korean Patent Application No. 10-2013-0108489, filed on Sep. 10, 2013, in the Korean Intellectual Property Office, and entitled: “BATTERY PACK,” is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     Embodiments relate to a battery pack. 
     2. Description of the Related Art 
     A battery pack may be used in a portable electronic device, such as a notebook computer, a personal digital assistant (PDA), a camcorder, and so on. The battery pack may be manufactured in a single body formed by grouping multiple bare cells. 
     A battery pack may be used in a high-capacity device having an increased number of bare cells, such as a garden tool, an e-bike, or the like. 
     SUMMARY 
     Embodiments are directed to a battery pack, including a plurality of bare cells, a first case covering one side of the bare cells, and a second case covering an opposite side of the bare cells and fastened to the first case. The first case may include fastening hooks formed on a sidewall of the first case that is to be coupled to the second case, and the second case may include fastening grooves formed on a sidewall of the second case that is to be coupled to the first case, the fastening grooves to be fastened to the fastening hooks, the fastening hooks including first fastening hooks protruding on a first region of the sidewall of the first case, the first fastening hooks being spaced apart from the plurality of bare cells in a first direction of the first case, the fastening hooks further including second fastening hooks protruding in a second direction opposite to the first direction, the first fastening hooks and the second fastening hooks being alternately arranged. 
     The battery pack may further include a protection circuit module provided between the bare cells and the first case, the protection circuit module being electrically connected to the bare cells. 
     The first case may include a receiving part formed on another sidewall adjacent to sidewall having the first region. 
     The receiving part may include coupling parts formed at opposite sides of the receiving part, and the receiving part may further include at least one first barrier part protruding between the coupling parts toward the bare cells and having a stepped portion. 
     The battery pack may further include a separator part that separates the receiving part from the bare cells. 
     The receiving part may include a display module received therein, the display module being electrically connected to the protection circuit module. 
     The first case may include a terminal part formed on a sidewall opposite to the sidewall having the receiving part, the terminal part being configured to electrically connect the protection circuit module to an external device. 
     The terminal part may include at least one second barrier part protruding on the sidewall having the terminal part toward the bare cells. 
     The second barrier part may be formed in a smaller number than the first barrier part. 
     The first fastening hooks and the second fastening hooks may be sequentially formed only in the first region of the sidewall of the first case. 
     The first fastening hooks and the second fastening hooks may be sequentially formed on the overall sidewall of the first case having the first region. 
     The first fastening hooks and the second fastening hooks may be alternately formed from the first region of the sidewall of the first case, the first fastening hooks and the second fastening hooks projecting in the first direction and the second direction in that order. 
     The second fastening hooks and the first fastening hooks may be alternately formed from the first region of the sidewall of the first case, the first fastening hooks and the second fastening hooks projecting in the second direction and the first direction in that order. 
     The fastening grooves may include first fastening grooves and second fastening grooves formed in the second case, the first fastening grooves and the second fastening grooves being located to correspond to the first fastening hooks and the second fastening hooks, respectively, so as to be engaged with the first fastening hooks and the second fastening hooks, respectively. 
     The first fastening grooves and the second fastening grooves may be shaped to fit the first fastening hooks and the second fastening hooks, respectively. 
     The first fastening grooves and the second fastening grooves may have shapes corresponding to shapes of the first fastening hooks and the second fastening hooks, respectively, so as to allow both of the first fastening hooks and the second fastening hooks to be engaged therewith. 
     At least one electrode tab may be provided at one side of the bare cells to electrically connect adjacent ones of the bare cells to each other. 
     An insulation tape for protecting the electrode tab may be provided between the electrode tab and an electrode tab adjacent to the electrode tab or an inner sidewall of the case. 
     The bare cells may be cylindrical lithium ion batteries. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features will become apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which: 
         FIG. 1  is a perspective view illustrating a battery pack according to an embodiment of the present invention; 
         FIG. 2  is an exploded perspective view illustrating the battery pack shown in  FIG. 1 ; 
         FIG. 3  illustrates a cross-sectional view taken along the line I-I of  FIG. 1 ; 
         FIG. 4  is an enlarged view illustrating an ‘A’ portion of  FIG. 3  in a state in which a fastening hook and a fastening groove have yet to be engaged with each other; 
         FIG. 5  is an enlarged view illustrating another embodiment of an ‘A’ portion of  FIG. 4 ; 
         FIG. 6  is a perspective view illustrating first fastening hooks and second fastening hooks of a first case in the battery pack shown in  FIG. 1 ; 
         FIG. 7  is a top view illustrating a first case in the battery pack shown in  FIG. 1 ; and 
         FIG. 8  is an enlarged perspective view illustrating a state in which a first case and a second case of the battery pack shown in  FIG. 1  are combined with each other. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art. 
     In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. 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. 
       FIG. 1  is a perspective view illustrating a battery pack according to an embodiment of the present invention,  FIG. 2  is an exploded perspective view illustrating the battery pack shown in  FIG. 1 ,  FIG. 3  is a cross-sectional view taken along the line I-I of  FIG. 1 ,  FIG. 4  is an enlarged view illustrating an ‘A’ portion of  FIG. 3  in a state in which a fastening hook and a fastening groove have yet to be engaged with each other,  FIG. 5  is an enlarged view illustrating another embodiment of an ‘A’ portion of  FIG. 4 ,  FIG. 6  is a perspective view illustrating first fastening hooks and second fastening hooks of a first case in the battery pack shown in  FIG. 1 ,  FIG. 7  is a top view illustrating a first case in the battery pack shown in  FIG. 1 , and  FIG. 8  is an enlarged perspective view illustrating a state in which a first case and a second case of the battery pack shown in  FIG. 1  are combined with each other. 
     Referring to  FIGS. 1 to 3 , a battery pack  100  according to an example embodiment may include a plurality of bare cells  200 , a protection circuit module  600 , and a case  300 . 
     As the bare cells  200 , rechargeable cylindrical secondary batteries or cylindrical secondary batteries may be used. In  FIG. 2 , the bare cells  200  including twenty bare cells are exemplified, but other numbers of bare cells  200  may be used. 
     Top and bottom surfaces of the bare cells  200  may have different polarities. The top surfaces of the bare cells  200  may correspond to positive electrodes, and the bottom surfaces of the bare cells  200  may correspond to negative electrodes. At least one electrode tab  210  may be provided at one side of the bare cells  200  to electrically connect adjacent ones of the bare cells  200 . 
     An insulation tape  220  for protecting the electrode tab  210  may be provided between the electrode tab  210  and an electrode tab adjacent to the electrode tab  210  or an inner sidewall of the case  300 . 
     The protection circuit module  600  may be provided between the bare cells  200  and the case  300 , and may be electrically connected to the bare cells  200 , e.g., through a plurality of wires  240 . The protection circuit module  600  may include protection circuit devices (not shown) for controlling charging and discharging, and may control charging and discharging of the bare cells  200 . The protection circuit module  600  may serve to prevent the bare cells  200  from being over-charged or over-discharged. 
     The protection circuit module  600  may include connectors  230 . The connectors  230  may be positioned on a surface of the battery pack  100  facing the outside, and may be fitted into terminal holes  441  formed in a terminal part  440  of the case  300 . 
     The terminal part  440  may include one or more barrier parts  442  (see  FIG. 7 ) protruding from the sidewall having the terminal part  440  toward the bare cells  200 . Adjacent ones of the terminal holes  441  may be separated from each other by the barrier parts  442 . The number of the barrier parts  442  may be, e.g., six. In an example embodiment, the barrier parts  442  may be formed in a smaller number than barrier parts  432  protruding on a receiving part  430 . The connectors  230  may serve as electrical paths to connect to an external electric device (not shown). 
     According to the present example embodiment, as shown in  FIGS. 1 and 2  the case  300  includes a first case  400  and a second case  500 . The case  300  includes the bare cells  200 , the protection circuit module  600 , and a display module  700 . 
     The first case  400  may include a first bottom part  410   a , a first sidewall  410   b , fastening hooks  420 , the receiving part  430 , and the terminal part  440 . 
     In the example embodiment shown in  FIG. 7 , the first case  400  is shaped of a box having an open top end to receive the bare cells  200 . The terminal part  440  having a predetermined size protrudes at one side of the first case  400  to receive the connectors  230 . As shown in  FIG. 2 , the bare cells  200 , the protection circuit module  600 , and the display module  700  may be placed in the first case  400 . 
     The first bottom part  410   a  is a surface on which the plurality of bare cells  200  are placed, and may be formed to be planar. The first bottom part  410   a  may be approximately two times thicker than the first sidewall  410   b  for purposes of preventing deterioration in the external appearance and creation of sink mark defects. 
     The first sidewall  410   b  upwardly extends from an edge of the first bottom part  410   a  to enclose the plurality of bare cells  200 . The first sidewall  410   b  includes a rib part  411  extending on a central portion of an upper side of the first sidewall  410   b . The rib part  411  may have a smaller thickness than the first sidewall  410   b.    
     According to the present example embodiment, the fastening hooks  420  upwardly extend from the central portion of the upper side of the first sidewall  410   b , and ends of the fastening hooks  420  protrude in a first direction or in a second direction opposite to the first direction of the first case  400 . For example, the fastening hooks  420  may protrude from the upper side of the rib part  411  to the inside or outside of the first case  400 . The fastening hooks  420  are fastened to the fastening grooves  520  of the second case  500  to combine the first case  400  and the second case  500  with each other. 
     According to the present example embodiment, as shown in  FIGS. 4 to 6 , the fastening hooks  420  include first fastening hooks  421  and second fastening hooks  422 . 
     The first fastening hooks  421  may protrude to the inside of the first case  400  (that is, in the first direction). The first fastening hooks  421  may be configured to have increasing heights from a top portion of the rib part  411 . For example, the first fastening hooks  421 , each having a vertical cross section shaped of a right triangle, may inwardly protrude to be easily engaged with the fastening grooves  520  of the second case  500 . Once the first fastening hooks  421  are engaged with the fastening grooves  520 , they may not be readily disengaged from the fastening grooves  520 . In addition, a thickness of the thickest part of the first fastening hook  421  may be greater than a thickness of the rib part  411 . 
     The second fastening hooks  422  may protrude to the outside of the first case  400  (that is, in the second direction). The second fastening hooks  422  may be configured to have increasing heights from the top portion of the rib part  411 . For example, the second fastening hooks  422 , each having a vertical cross section shaped of a right triangle, may outwardly protrude (which is opposite to the direction in which the first fastening hooks  421  protrude) to be easily engaged with the fastening grooves  520  of the second case  500 . Once the second fastening hooks  422  are engaged with the fastening grooves  520 , they may not be readily disengaged from the fastening grooves  520 . In addition, a thickness of the thickest part of the second fastening hook  422  may be greater than the thickness of the rib part  411 . 
     The first fastening hooks  421  and the second fastening hooks  422  may be sequentially arranged on a first region B of the first sidewall  410   b , spaced apart from the bare cells  200 , to alternate each other. The first region B is a region where the receiving part  430  of the first case  400  is formed. 
     The first fastening hooks  421  and the second fastening hooks  422  may be arranged in groups of, e.g., 2 or 4 hooks, and may be spaced apart from each other. In addition, numbers of the first fastening hooks  421  and the second fastening hooks  422  may vary according to the number of the bare cells  200  and the size of the case  300 . In addition, the numbers and shapes of the first fastening hooks  421  and the second fastening hooks  422  may also vary according to the size and design of the first case  400 . In the present example embodiment, the first fastening hooks  421  and the second fastening hooks  422  are alternately arranged on the first sidewall  410   b  in the first region B having the receiving part  430 . When the first case  400  and the second case  500  are combined with each other, the first fastening hooks  421  and the second fastening books  422  are fixed to the fastening grooves  520  of the second case  500  in opposite directions in the first region B, where the first case  400  and the second case  500  are combined with each other with a relatively weak coupling force, which may improve the coupling force of the first case  400  and the second case  500  in the first region B. 
     In addition, the first fastening hooks  421  and the second fastening hooks  422  may be sequentially formed on the overall first sidewall  410   b  having the first region. In the present example embodiment, the first fastening hooks  421  and the second fastening hooks  422  are alternately arranged on the overall first sidewall  410   b  to combine the first case  400  with the second case  50 . In such a case, the first fastening hooks  421  and the second fastening hooks  422  are fixed to the fastening grooves  520  of the second case  500 , which may improve the coupling force of the first case  400  and the second case  500 . 
     In addition, the first fastening hooks  421  and the second fastening hooks  422  may be alternately formed from the first region B of the first sidewall  410   b  in the first direction and the second direction in that order. In another implementation, the second fastening hooks  422  and the second fastening hooks  421  may be alternately formed from the first region B of the first sidewall  410   b  in the second direction and the first direction in that order. 
     According to the present example embodiment, the receiving part  430  is formed on the other sidewall adjacent to the first region B on the first sidewall  410   b  in the first case  400 . The receiving part  430  may be formed to have a predetermined receiving space on one sidewall of the first case  400 . The receiving part  430  may be separated from the bare cells  200  through a separator part  460 . The separator part  460  may be a separating barrier formed to be parallel with the display module  700 , and a plurality of support barriers  1461  vertically supporting the display module  700  may be formed on the separator part  460 . 
     The receiving part  430 , including the coupling parts  431  and the barrier parts  432 , may form a receiving space. 
     Each of the coupling parts  431  may be formed in a “U” shape to have both sides facing each other. The display module  700  may be inserted into an inside  431   a  between the both sides of the “U” shaped coupling part  431  in an interference fit manner. A width W of the inside  431   a  of the “U” shaped coupling part  431  may be equal to or smaller than a width of the display module  700 . 
     The barrier parts  432  may be plurally provided and may protrude between the coupling parts  431  toward the bare cells  200  from a sidewall  410   c  opposite to the terminal part  440 . Substantially “L” shaped stepped portions  432   a  may be formed at lower regions of the barrier parts  432 , and the display module  700  may be fitted into the coupling part  431  and fixed in parallel to a top surface of a region having the stepped portions  432   a.    
     The display module  700  may be inserted into the receiving part  430  formed on one sidewall of the first case  400  in an interference fit manner. The display module  700  may be electrically connected to the protection circuit module  600  and may externally display, e.g., the number, capacity, or charged or discharged states of the bare cells  200 . 
     Even if the first case  400  connected with the display module  700  is combined with the second case  500 , the coupling force between the first case  400  and the second case  500  may be weakened by external impacts due to spaces between one sidewall of each of the first case  400  and the second case  500  and the bare cells  200 , thereby allowing the first case  400  and the second case  500  to be easily disengaged from each other. In the present example embodiment, the first fastening hooks  421  and the second fastening hooks  422 , which are alternately formed on the first region B adjacent to the one sidewall of the first case  400  connected with the display module  700 , are engaged with the fastening grooves  520  formed in the second case  500 , which may improve the coupling force of the case  300  and improve stability against external impacts. 
     The terminal part  440  may protrude on the sidewall opposite to the sidewall having the receiving part  430 . The terminal part  440  may have a plurality of terminal holes  441  formed therein, the terminal holes  441  spaced a predetermined distance apart from each other and passing through the terminal part  440  terminal part  440 . A plurality of connectors  230  may be fitted into the terminal holes  441 , such that one side of each of the terminal holes  441  is electrically connected to the protection circuit module  600  and the other side of each of the terminal holes  441  is electrically connected to a terminal of an external device. 
     According to the present example embodiment, the second case  500  includes a second top part  510   a , a second sidewall  510   b , and fastening grooves  520 . 
     The second case  500  may be shaped as a box having an open bottom end to receive the plurality of bare cells  200 . The second case  500  may be sized to fit the first case  400  and may cover the first case  400 . 
     The second sidewall  510   b  extends from edges of the second top part  510   a.    
     The fastening grooves  520  are formed on the second sidewall  510   b  to be located to fit the fastening hooks  420  of the rib  411 . Since the fastening grooves  520  are located to fit the fastening hooks  420  of the rib  411 , they are engaged with the fastening hooks  420 . Since the fastening grooves  520  are engaged with the fastening hooks  420  of the first case  400 , the first case  400  and the second case  500  are combined with each other. The number of the fastening grooves  520  may be equivalent to that of the fastening hooks  420  of the first case  400 . 
     According to the present example embodiment, the fastening grooves  520  are formed on the second sidewall  510   b  to be located to fit the first fastening hooks  421  and the second fastening hooks  422  formed on the rib  411 , and are engaged with the first fastening hooks  421  and the second fastening hooks  422 . Thus, the fastening grooves  520  are located to fit the first region B having the first fastening hooks  421  and the second fastening hooks  422 . 
     As shown in  FIG. 4 , the fastening grooves  520  may be shaped to fit the first fastening hooks  421  and the second fastening hooks  422 . Thus, each of the fastening grooves  520  may have a central region  520   a  of the second sidewall  510   b  and a groove  520   b  formed into the inside of the second case  500  to be engaged with the first fastening hooks  421  protruding to the inside of the first case  400 . In addition, each of the fastening grooves  520  may have a central region  520   a  of the second sidewall  510   b  and a groove (not shown) formed into the outside of the second case  500  to be engaged with the second fastening hooks  422  protruding to the outside of the first case  400 . In the present example embodiment, the grooves  520   b  engaged with the first fastening hooks  421  and the grooves engaged with the second fastening hooks  422  are alternately arranged. 
     In another implementation of the fastening grooves  520 , as shown in  FIG. 5 , fastening grooves  530  may be shaped to allow both of the first fastening hooks  421  and the second fastening hooks  422  to be engaged therewith. Thus, each of the fastening grooves  520  may include a central region  530   a  of the second sidewall  510   b  and a groove formed to both of an inside  530   c  and an outside  530   c  of the second case  500  to accommodate all of the rib  411 , the first fastening hooks  421  protruding to the inside of the first case  400 , and the second fastening hooks  422  protruding to the outside of the first case  400 . 
     The combining of the first case  400  with the second case  500  will now be described in detail with reference to  FIGS. 4 ,  5 , and  7 . 
     The combining of the first case  400  with the second case  500  may be achieved by engagement based on locking structures of the fastening hooks  420  and the fastening grooves  520 . In the first case  400 , the first fastening hooks  421  and the second fastening hooks  422  protruding to the inside and the outside may be inserted into the fastening grooves  520 . The first fastening hooks  421  and the second fastening hooks  422  are engaged with the fastening grooves  520 . Since the first fastening hooks  421  and the second fastening hooks  422  of the first case  400  are engaged with the fastening grooves  520  of the second case  500 , the first case  400  and the second case  500  are combined with each other. 
     In a case where the first fastening hooks  421  and the second fastening hooks  422  are formed only in the first region B of the first case  400 , the first fastening hooks  421  and the second fastening hooks  422  may be engaged with the fastening grooves  520  in opposite directions in the first region B, where the first case  400  and the second case  500  are combined with each other with a relatively weak coupling force, which may increase the coupling force between the first case  400  and the second case  500 . 
     In addition, in a case where the first fastening hooks  421  and the second fastening hooks  422  are formed on the overall region of the first sidewall  410   b  of the first case  400 , they may be engaged with the fastening grooves  520  in opposite directions on the overall region of the first sidewall  410   b  of the first case  400 , which may increase the coupling force between the first and second fastening hooks  421  and  422  and the fastening grooves  520 . 
     As described above, in the battery pack  100  according to an example embodiment, the first fastening hooks  421  and the second fastening hooks  422  protruding in opposite directions are formed on the first sidewall  410   b  of the first case  400  to be engaged with the fastening grooves  520  in opposite directions, which may increase the coupling force between the first case  400  and the second case  500 . 
     Accordingly, the fastening hooks of the first case  400  and the fastening grooves  520  of the second case  500  may be engaged with each other with increased coupling forces without deterioration in the external appearance quality. Therefore, even if external impacts are applied to the battery pack  100 , the first case  400  and the second case  500  may not be readily separated from each other. 
     In order to improve the coupling force between the first case  400  and the second case  500 , a plurality of fasteners  450  may be additionally provided. 
     By way of summation and review, a battery pack may include a first case having a plurality of fastening books formed along its periphery, a second case having a plurality of fastening grooves located to correspond to the fastening hooks of the first case, and a plurality of bare cells received in a space formed by the first case and the second case. Due to the increasing weight of the high-capacity battery pack from increasing the number of bare cells, increasing the coupling force between cases of the battery pack may be important. In a general battery pack in which fastening hooks are arranged in only one direction, when fastening hooks of the first case are engaged with fastening grooves of the second case, the coupling force may be reduced when an impact is applied to the battery pack. 
     As described above, embodiments are directed to a battery pack that may have an improved coupling force. The battery pack according to an example embodiment may have an improved coupling force in a coupled portion of a case by forming hooks in opposite directions, compared to a case having hooks formed in only one direction. 
     Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.