Abstract:
A battery pack includes a first battery module, the first battery module including first unit batteries arranged side by side in a first direction, a second battery module adjacent to the first battery module, the second battery module including second unit batteries arranged side by side in the first direction, and at least one supporting block in a space between the first unit batteries and the second unit batteries, the at least one supporting block contacting the first and second battery modules.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application No. 61/272,929, filed in the U.S. Patent and Trademark Office on Nov. 19, 2009, and entitled “BATTERY PACK,” which is incorporated by reference herein in its entirety and for all purposes. 
    
    
     BACKGROUND 
     1. Field 
     Embodiments relate to a battery pack. 
     2. Description of the Related Art 
     Secondary batteries are rechargeable and dischargeable. Secondary batteries are broadly used in high-tech electronic devices such as cellular phones, notebook computers, and camcorders, and are also used in vehicles. 
     A secondary battery may include an electrode assembly and an electrolyte. The electrode assembly may include a positive plate, a negative plate, and a separator. The electrolyte may include lithium ions. The positive plate and the negative plate of the electrode assembly may include electrode tabs protruding outward. 
     The electrode assembly may be accommodated in a case, and electrode terminals may be exposed outside the case. The electrode tabs may protrude outside the electrode assembly so as to be electrically connected to the electrode terminals. The case may have, e.g., a cylindrical shape or an angular shape. 
     A plurality of unit battery cells that are secondary batteries may be horizontally or vertically stacked so as to form a battery module. Also, a plurality of battery modules may be vertically and/or horizontally stacked so as to form one battery pack. 
     SUMMARY 
     It is a feature of an embodiment to provide a battery pack formed by vertically and/or horizontally stacking battery modules, each of which is formed by stacking a plurality of unit battery cells, in which deflection of the battery modules may be reduced. 
     At least one of the above and other features and advantages may be realized by providing a battery pack, including a first battery module, the first battery module including first unit batteries arranged side by side in a first direction, a second battery module adjacent to the first battery module, the second battery module including second unit batteries arranged side by side in the first direction, and at least one supporting block in a space between the first unit batteries and the second unit batteries, the at least one supporting block contacting the first and second battery modules. 
     The first and second battery modules may extend in a substantially horizontal direction, and the at least one supporting block may rests on the second unit batteries and support the first unit batteries. 
     The first and second battery modules may be spaced apart in a second direction, the second direction being normal to the first direction. 
     The supporting blocks may be arranged so as to uniformly distribute the weight of the first battery module on the second battery module. 
     The at least one supporting block may contact the first and second unit batteries. 
     The second unit batteries may be arranged such that sides of two adjacent second unit batteries are proximate to one another, and a supporting block rests on both of the two adjacent second unit batteries. 
     The at least one supporting block may include an elastic member that is elastically deformable in a direction normal to the first direction. 
     The elastic member may be a rubber member. 
     The at least one supporting block may be compressed in the battery pack, the at least one supporting block having a length, when uncompressed, that is larger than that of the space. 
     The at least one supporting block may be fixed to the second battery module. 
     The battery pack may further include an adhesive member fixing the at least one supporting block to the second battery module. 
     The battery pack may further include at least one additional battery module, the at least one additional battery module being combined with the first and second battery modules in a vertical stack, wherein at least one supporting block is disposed between adjacent battery modules in the vertical stack. 
     The first battery module may include first battery module end plates disposed at respective ends of the first battery module, the second battery module may include second battery module end plates at respective ends of the second battery module, and the first and second battery module end plates may support the first unit batteries such that the space is between the first unit batteries and the second unit batteries. 
     The battery pack may further include side frames extending in the first direction, the side frames being coupled to the second battery module end plates and supporting the second unit batteries from side surfaces of the second unit batteries. 
     The battery pack may further include a rigid member extending in the first direction, the rigid member being coupled to the second battery module end plates and supporting surfaces of the second unit batteries that are opposite to the first battery module. 
     At least one of the above and other features and advantages may also be realized by providing a vehicle, including a power source, the power source providing a motive power for the vehicle, and a battery pack configured to provide electricity to the power source, the battery pack including a first battery module, the first battery module including first unit batteries arranged side by side in a first direction, a second battery module adjacent to the first battery module, the second battery module including second unit batteries arranged side by side in the first direction, and at least one supporting block in a space between the first unit batteries and the second unit batteries, the at least one supporting block contacting the first and second battery modules. 
     At least one of the above and other features and advantages may also be realized by providing a method of stiffening a battery pack, the method including fixing first and second battery modules in a vertical stack, the first and second battery modules having respective end plates fixed together in a vertical direction so as to define a space between the first and second battery modules, and providing at least one supporting block in the space, the at least one supporting block resting on unit batteries of the second battery module and supporting the first battery module. 
     At least one of the above and other features and advantages may also be realized by providing a method of forming a battery pack, the method including providing a first battery module, the first battery module including first unit batteries arranged side by side in a first direction, arranging a second battery module adjacent to the first battery module, the second battery module including second unit batteries arranged side by side in the first direction, and providing at least one supporting block in the space between the first unit batteries and the second unit batteries, the at least one supporting block contacting the first and second battery modules. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages will become more apparent to those of skill in the art by describing in detail example embodiments with reference to the attached drawings, in which: 
         FIG. 1  illustrates a perspective view of a battery module in which a plurality of battery cells are horizontally stacked, according to an embodiment; 
         FIG. 2  illustrates an exploded perspective view of the battery module of  FIG. 1 ; 
         FIG. 3  illustrates a perspective view of a unit battery cell included in the battery module of  FIG. 1 , according to an embodiment; 
         FIG. 4  illustrates a perspective view of vertically stacked battery modules between which supporting blocks are disposed, according to an embodiment; 
         FIG. 5  illustrates a perspective view of the battery modules of  FIG. 4  when the battery modules are separated; 
         FIG. 6  illustrates a perspective view of a battery pack in which a plurality of the battery modules of  FIG. 1  are vertically and horizontally stacked and are supported by an external frame, according to an embodiment; and 
         FIG. 7  illustrates an electric car  1  using the battery pack  10  described above in connection with  FIG. 6 , according to an embodiment. 
     
    
    
     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 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. 
     A battery pack  10  according to an embodiment may be formed by vertically and/or horizontally stacking one or more battery modules  100 . Also, each of the battery modules  100  may be formed by vertically and/or horizontally stacking one or more unit battery cells  110 . 
     In this case, as illustrated in  FIGS. 4 and 5 , the battery pack  10  may be formed by vertically stacking a plurality of battery modules  100   a  and  100   b . Battery modules  100   a  and  100   b  include a upper battery module  100   a  and a lower battery module  100   b  which are vertically stacked together. 
     When the battery modules  100   a  and  100   b  are vertically stacked, the upper battery module  100   a  may be deflected due to the weight of a plurality of unit battery cells  110 . Also, vibration of the battery modules  100  may occur due to the deflection of the upper battery module  100   a . However, in the battery pack  10  according to an embodiment, one or more supporting blocks  200  may be formed between the battery modules  100   a  and  100   b  that are vertically stacked. In this case, the supporting blocks  200  may reduce deflection and vibration of the battery modules  100  by supporting portions of the battery modules  100  to be deflected. 
       FIG. 1  illustrates a perspective view of battery module  100  in which a plurality of battery cells  110  are horizontally stacked, according to an embodiment.  FIG. 2  illustrates an exploded perspective view of the battery module  100  illustrated in  FIG. 1 . A battery pack may be formed by vertically and/or horizontally stacking a plurality of the battery modules  100 . 
     Referring to  FIGS. 1 and 2 , the battery module  100  may include a plurality of unit battery cells  110 , an upper frame  120 , a lower frame  130 , side frames  140 , and end plates  150 . 
     The unit battery cells  110  may be stacked in a first direction so as to form the battery module  100 . The upper frame  120  may be disposed on the unit battery cells  110  stacked in the first direction so as to support the unit battery cells  110  in a second direction from upper surfaces of the unit battery cells  110 . The lower frame  130  may be disposed under the unit battery cells  110  stacked in the first direction so as to support the unit battery cells  110  from lower surfaces of the unit battery cells  110 . 
     The side frames  140  may be disposed at sides of the unit battery cells  110  stacked in the first direction so as to support the unit battery cells  110  from side surfaces of the unit battery cells  110 . A pair of the end plates  150  may be disposed at ends of the unit battery cells  110  stacked in the first direction so as to support the unit battery cells  110  from the ends of the unit battery cells  110 . 
     Here, the first direction may be an X direction and the second direction may be a Z direction. In this case, if the battery modules  100  are horizontally arranged, the X direction may be a horizontal direction and the Z direction may be a vertical direction. However, embodiments are not limited thereto, and the X and Z directions may differ according to the arrangement direction of the battery modules  100 . 
       FIG. 3  illustrates a perspective view of a unit battery cell  110  included in the battery module  100  illustrated in  FIG. 1 , according to an embodiment. A plurality of the unit battery cells  110  may be stacked in a horizontal direction so as to form the battery module  100 . The unit battery cell  110  may be generally formed in an angular shape as illustrated in  FIG. 3 . However, embodiments are not limited thereto, and the unit battery cell  110  may have various shapes such as a cylindrical shape or a pouch shape. 
     Referring to  FIGS. 1 ,  2 , and  3 , a general secondary battery may be used as the unit battery cell  110 . The secondary battery may include an electrode assembly and an electrolyte. The electrode assembly may include a positive plate, a negative plate, and a separator. The electrolyte may include lithium ions. The positive plate and the negative plate of the electrode assembly may protrude outward so as to be electrically connected to a current collector. 
     The electrode assembly may be accommodated in a case  111 , and electrode terminals  112  may be exposed outside the case  111 . Respective current collectors, electrically connected to the positive plate or the negative plate, may be electrically connected to the electrode terminals  112 . The case  111  may have a cylindrical shape or an angular shape. The unit battery cell  110  may include a plurality of electrode assemblies in one case  111 . 
     The unit battery cells  110  may be horizontally stacked so as to form the battery module  100 . In the battery module  100 , the electrode terminals  112  of neighboring unit battery cells  110  may be electrically connected to each other. In this case, the electrode terminals  112  of the neighboring unit battery cells  110  may be electrically connected to each other by using, e.g., bus bars  116 . 
     The neighboring unit battery cells  110  may be disposed so that their polarities are opposite to each other. The unit battery cells  110  may be connected in parallel, in series, or in parallel and series. As such, the unit battery cells  110  may be sequentially connected to each other so as to form one battery module  100 . The connection method and the number of the unit battery cells  110  may be determined in consideration of required capacities of recharge or discharge when the unit battery cells  110  are designed. 
     A cap plate  113  may be combined with an opening portion of the case  111  to close the case  111 . The cap plate  113  may be a thin plate. An electrolyte inlet for injecting the electrolyte into the case  111  may be formed in the cap plate  113 . The electrolyte inlet may be sealed with a sealing plug  114  after the electrolyte is injected. 
     A vent member  115 , in which grooves are formed, may be formed on the cap plate  113  such that the vent member  115  may be broken when a set internal pressure is reached. If the upper frame  120  is disposed on the unit battery cells  110  that are horizontally stacked, an exhaust outlet  121  of the upper frame  120  may be disposed on the vent member  115 . 
     The unit battery cell  110  illustrated in  FIG. 3  may be a lithium-ion secondary battery. However, embodiments are not limited thereto, and, in addition to the lithium-ion secondary battery, various batteries, such as a nickel-cadmium secondary battery, a nickel-hydrogen secondary battery, and a lithium battery, may be used as the unit battery cell  110 . 
     In a unit battery cell  110  containing lithium, the electrode assembly may expand or contract when recharge or discharge occurs. In this case, the expansion and the contraction of the electrode assembly may apply physical force to the case  111 . Accordingly, the case  111  may physically expand and contract in correspondence with the expansion and the contraction of the electrode assembly. 
     The case  111  may be deformed due to repeated expansion and contraction. The expansion in volume may increase resistance so as to reduce the efficiency of the unit battery cell  110 . In this regard, a pair of the end plates  150  may be disposed at two ends of the unit battery cells  110  that are horizontally and/or vertically arranged and are electrically connected to each other. For example, the upper frame  120 , the lower frame  130  and the side frames  140  may be respectively supported on upper, lower, and side surfaces of the end plates  150 , and may compressively fix the unit battery cells  110  so as to reduce or eliminate horizontal expansion due to the expansion of the unit battery cells  110 . 
     The end plates  150  may be disposed at two ends of the battery module  100 . A pair of the end plates  150  may respectively contact outer surfaces of the unit battery cells  110  disposed at two ends of the battery module  100 , so as to support the stacked unit battery cells  110 . 
     An end plate  150  may include a base plate  151 , and flanges  152 ,  153 , and  154 . The base plate  151  may have a size that is sufficient to cover an outer surface of the unit battery cells  110 . Although the base plate  111  has an almost square shape in  FIGS. 1 and 2 , the shape of the base plate  111  is not limited thereto. The flanges  152 ,  153 , and  154  may be bent from the base plate  151  away from the unit battery cells  110 . 
     The flanges  152 ,  153 , and  154  may include upper flanges  152 , a lower flange  153 , and side flanges  154 . The upper flanges  152  may be combined with the upper frame  120 . The lower flange  153  may be combined with the lower frame  130 . The side flanges  154  may be correspondingly combined with the side frames  140 . 
     A plurality of the battery modules  100  may be vertically and/or horizontally stacked so as to form the battery pack. In this case, the end plates  150  of neighboring battery modules  100  may be combined with each other so as to support each other. 
     For example, the upper flanges  152  of a first battery module  100  may be combined with the lower flanges  153  of a second battery module  100 . Further, the lower flanges  153  of the first battery module  100  may be combined with the upper flanges  152  of a third battery module  100 . In another implementation, the side flanges  154  of the first battery module  100  may be combined with the side flanges  154  of a fourth battery module  100  disposed alongside. 
     The upper, lower, and side flanges  152 ,  153 , and  154  may be respectively combined with the upper, lower, and side frames  120 ,  130 , and  140  by, e.g., screwing them together using bolts and nuts. However, embodiments are not limited thereto, and the upper, lower, and side flanges  152 ,  153 , and  154  may be respectively combined with the upper, lower, and side frames  120 ,  130 , and  140  by using various methods such as a welding method, riveting, etc. 
     The upper frame  120  may be disposed on the unit battery cells  110  that are horizontally stacked, and may be combined with the upper flanges  152  of the end plates  150 . In this case, the exhaust outlets  121  may be formed in the upper frame  120  in correspondence with the vent members  115  of the unit battery cells  110 . 
     The upper frame  120  may have upper frame bent portions  122 , which may be bent from lengthwise edges of the upper frame  120 . A sealing member  123  may be formed on inner sides of the upper frame bent portions  122 . The sealing member  123  may be formed of, e.g., an elastic material such as rubber. The upper frame  120  may be combined with the lower frame  130  of the upper battery module  100  with the sealing member  123  interposed therebetween so as to form a gas passage for discharging a sealed gas. 
     Sealing rings  117  may be formed between the upper frame  120  and the vent members  115  such that a gas ejected from the vent members  115  flows out through the exhaust outlets  121  of the upper frame  120  without influencing a neighboring unit battery cell  110 . For example, O-rings may be used as the sealing rings  117 . In this case, grooves  152   a  in which the upper frame  120  is to be disposed may be formed in the middle of upper edges of the end plates  150 . Thus, the exhaust outlets  121  of the upper frame  120  may contact the unit battery cells  110 . 
     Also, the sealing rings  117  between the unit battery cells  110  and the upper frame  120  may have a sufficient thickness. Accordingly, when the upper frame  120  is combined with the end plates  150 , the upper frame  120  may generate pressure on the unit battery cells  110  so as to compress the sealing rings  117  disposed therebetween, and thus the upper frame  120  may contact the unit battery cells  110 . 
     The lower frame  130  may be disposed under the unit battery cells  110  so as to support the weight of the unit battery cells  110 , and may be connected to the lower flanges  153  of the end plates  150 . In order to support the weight of the unit battery cells  110 , the lower frame  130  may include lower frame bent portions  132  bent away from the unit battery cells  110 . The bent shape may make the lower frame  130  more rigid. 
     The lower frame bent portions  132  may be open downward. Also, the lower frame bent portions  132  may be combined with the upper frame  120  of the lower battery module  100  so as to form a gas passage. 
     The gas passage formed by combining the lower frame  130  of an upper battery module  100  and the upper frame  120  of a lower battery module  100  may function as a degassing duct for discharging a generated gas. The lower frame  130  of the upper battery module  100  and the upper frame  120  of the lower battery modules  100  may degas in a sealed state or may induce degassing even in an incompletely sealed state. A gas generated in the unit battery cells  110  may be accompanied with an explosion or a rapid chemical reaction corresponding to an explosion, and thus the amount of the gas is explosively increased in a short time. Thus, if a degassing duct is formed in the battery pack, the gas may be easily discharged. 
     The side frames  140  may be disposed at sides of the unit battery cells  110  so as to support the unit battery cells  110  from side surfaces of the unit battery cells  110 . The side frames  140  may extend with a uniform width from one of a pair of the end plates  150  to the other of the pair of the end plates  150 . 
     One or more through holes  141  may be formed in each of the side frames  140  so as to reduce the weight of the side frames  140 . Also, the side frames  140  may include side frame bent portions  142  bent away from the unit battery cells  110 . The side frame bent portions  142  may increase the strength and rigidity of the side frames  140  against bending. 
     One or more supporting blocks  200  may be formed between the battery modules  100 , which may be stacked, e.g., vertically. In this case, the supporting blocks  200  may reduce deflection and vibration of the battery module  100  by supporting portions of the battery modules  100  to be deflected. 
       FIG. 4  illustrates a perspective view of vertically stacked battery modules  100   a  and  100   b , between which supporting blocks  200  are disposed, according to an embodiment.  FIG. 5  illustrates a perspective view of the battery modules  100   a  and  100   b  illustrated in  FIG. 4  when the battery modules  100  are separated. 
     Referring to  FIGS. 4 and 5 , the battery pack  10  may be formed by vertically stacking a plurality of battery modules. The plurality of battery modules may include a upper battery module  100   a  and a lower battery module  100   b  which are vertically stacked together. 
     In the battery pack  10  having the battery modules  100   a  and  100   b , the supporting blocks  200  may contact upper surfaces of unit battery cells  110  of the lower battery module  100   b  and lower surfaces of unit battery cells  110  of the upper battery module  100   a.    
     In an implementation, double-sided tape may be adhered to upper and lower surfaces of the supporting blocks  200 , such that the supporting blocks  200  may be adhered and fixed to the battery modules  100   a  and  100   b . In an implementation, an adhesive agent may be coated on contact portions of the supporting blocks  200  and the battery modules  100   a  and  100   b , so as to adhere the supporting blocks  200  to the battery modules  100   a  and  100   b . However, embodiments are not limited thereto, and the supporting blocks  200  may be fixed to the battery modules  100   a  and  100   b  by using various methods, or may supported due to the pressure between the battery modules  100   a  and  100   b  without using an additional fixing means. 
     A plurality of the supporting blocks  200  may be used. The supporting blocks  200  may be disposed so as to uniformly distribute the weight of the upper battery module  100   a  to be supported. For example, the same number of the supporting blocks  200  may be disposed at two sides with respect to the upper frame  120 . In this case, an even number of the supporting blocks  200  may be disposed. 
     The supporting blocks  200  may be formed as elastic members such that the battery modules  100   a  and  100   b  elastically support each other. For example, the supporting blocks  200  may be rubber blocks. In an implementation, the supporting blocks  200  may be formed to have a height slightly greater than the distance between the unit battery cells  110  of the battery modules  100   a  and  100   b , so as to provide elastic bias. 
     The supporting blocks  200  may be formed in a shape such as a cylindrical shape, a polygonal pillar shape, or a barrel shape. In an implementation, in order to stably contact the unit battery cells  110 , surfaces of the supporting blocks  200  to contact the unit battery cells  110  may be formed to be flat. However, the shape of the supporting blocks  200  is not limited thereto, and may be variously changed. 
     Through holes or grooves may be formed in surfaces of the supporting blocks  200  to contact the unit battery cells  110 . In this case, the elastic force of the supporting blocks  200  may be increased. The supporting blocks  200  may reduce deflection and vibration of the upper battery module  100   a  by supporting portions of the upper battery module  100   a  to be deflected. 
     The upper battery module  100   a , when disposed at the top layer, may further include a cover  125  for covering the upper frame  120 . In an implementation, the cover  125  may form a degassing duct for discharging a gas generated in the top battery module  100   a.    
       FIG. 6  illustrates a perspective view of a battery pack  10  in which a plurality of the battery modules  100  illustrated in  FIG. 1  are vertically and horizontally stacked and are supported by an external frame  300 , according to an embodiment. 
     Referring to  FIG. 6 , the battery pack  10  may be formed by stacking eight battery modules  100 , each of which is formed by horizontally stacking the unit battery cells  110 , in two columns of four layers, and combining the battery modules  100 . 
       FIG. 7  illustrates an electric car  1  using a battery pack  10  according to an embodiment. 
     Referring to  FIG. 7 , the battery pack  10  according to an embodiment may be equipped in the body  500  of the electric car  1 . In the electric car  1  using the battery pack  10 , as the electric car  1  runs, a dynamic load may be applied to the battery pack  10 . In this case, deflection and/or vibration may occur in the battery modules  100  that are vertical and/or horizontally stacked. However, in the battery pack  10  according to an embodiment, the supporting blocks  200  may reduce the deflection and vibration of the battery modules  100  by supporting portions of the battery modules  100  to be deflected. 
     As described above, embodiments relate to a battery pack, and to a battery pack formed by vertically or horizontally stacking battery modules, each of which is formed by stacking a plurality of unit battery cells. According to the one or more embodiments, in a battery pack formed by vertically or horizontally stacking battery modules, each of which is formed by stacking a plurality of unit battery cells, deflection of the battery modules may be reduced. 
     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. 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.