Patent Publication Number: US-2016226116-A1

Title: Battery pack

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Korean Patent Application No. 10-2015-0015591, filed on Jan. 30, 2015, in the Korean Intellectual Property Office, and entitled “Battery Pack,” is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     One or more exemplary embodiments relate to a battery pack. 
     2. Description of the Related Art 
     Secondary batteries may be rechargeable unlike primary batteries that cannot be recharged. The secondary batteries may be used as energy sources in, for example, mobile devices, electric vehicles, hybrid vehicles, electric bicycles, and uninterruptible power supplies, and may be of a single-battery type or a pack type in which multiple batteries may be electrically connected to each other and bound in one unit, according to types of external devices using the secondary batteries. 
     SUMMARY 
     Embodiments may be realized by providing a battery pack, including a plurality of battery cells; and first spacers and second spacers between the plurality of battery cells to form gap flow paths, the first spacers and second spacers extending to face each other, the first spacers extending from a first position and the second spacers extending from a second position, the first and second positions facing each other such that the first and second spacers interlock. 
     The first spacers and second spacers may extend at least to locations where end portions of the first spacers overlap end portions of the second spacers. 
     End portions of the first spacers may extend toward the second position, but may not reach the second position. 
     End portions of the second spacers may extend toward the first position, but may not reach the first position. 
     Each of the first spacers and the second spacers may include a plurality of unit members between neighboring battery cells. 
     Each of the plurality of unit members may have a pole shape extending in one direction. 
     The first position may correspond to a first case, the second position may correspond to a second case, and the first and second cases may be coupled to each other along upward and downward directions, in which the first spacers and second spacers face each other, by interposing the plurality of battery cells between the first and second cases. 
     The first spacers may extend from the first case to the second case, and end portions of the first spacers may be separated from the second case, and the second spacers may extend from the second case to the first case, and end portions of the second spacers may be separated from the first case. 
     The gap flow paths may include a space between the first spacers and the second case, a space between the first and second spacers interlocking with one another in a comb form, and a space between the second spacers and the first case. 
     The gap flow paths may induce air flow in a zigzag pattern reciprocating along the upward and downward directions. 
     The battery cells may include battery cells aligned in a first column and a second column, and a main flow path connected to a fluid machine may be formed between the battery cells in the first column and the battery cells in the second column. 
     The battery cells in the first column and the battery cells in the second column may be aligned diagonally with respect to the main flow path. 
     The battery cells in the first column and the battery cells in the second column may be symmetrically aligned with respect to the main flow path. 
     The battery pack may further include a first case and a second case coupled to each other in upward and downward directions, the first spacers and second spacers facing each other in the upward and downward directions, the first and second cases providing a space for housing the battery cells. The first case may have a box shape including a bottom portion, side portions for forming the space, and an open upper portion, and the second case may have a plate shape that covers the open upper portion of the first case. 
     The main flow path may be formed in a front-rear direction of the first case, the battery cells in the first column and the battery cells in the second column may be aligned on left and right sides of the main flow path, one of the side portions may be on a front of the first case, the one side portion may include a first through hole, and side portions on left and right sides of the first case may each include a second through hole. 
     The first through hole may be connected to the fluid machine and may discharge air to outside the battery pack, and the second through holes may receive air from outside the battery pack. 
     The fluid machine may generate air flow by using a suction force. 
    
    
     
       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  illustrates a perspective view of a battery pack according to an exemplary embodiment; 
         FIG. 2  illustrates an exploded perspective view of the battery pack of  FIG. 1 ; 
         FIG. 3  illustrates a plan structure of a first case of  FIG. 1 ; 
         FIG. 4  schematically illustrates air flow in the battery pack of  FIG. 1 ; and 
         FIG. 5  illustrates a cross-sectional view taken along a line V-V of  FIG. 2  (not indicated in  FIG. 2 ) and schematically illustrates air flow in neighboring battery cells. 
     
    
    
     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. Like reference numerals refer to like elements throughout. 
     Hereinafter, a battery pack will be described in detail by explaining exemplary embodiments with reference to the attached drawings. 
       FIG. 1  illustrates a perspective view of a battery pack according to an exemplary embodiment.  FIG. 2  illustrates an exploded perspective view of the battery pack of  FIG. 1 .  FIG. 3  illustrates a plan structure of a first case  110  of  FIG. 1 .  FIG. 4  schematically illustrates air flow in the battery pack of  FIG. 1 . Also,  FIG. 5  illustrates a cross-sectional view taken along a line V-V of  FIG. 2  (not indicated in  FIG. 2 ) and schematically illustrates air flow in neighboring battery cells. For convenience of illustration, the battery cells are not illustrated in  FIG. 1 . 
     Referring to the attached drawings, the battery pack may include at least two battery cells  10  and spacers  131  and  132  aligned between the battery cells  10 . The spacers  131  and  132  may induce air flow in a reciprocating zigzag pattern between the neighboring battery cells  10 . 
     The battery cells  10  may be aligned in a first column R 1  and a second column R 2 . The battery cells  10  in the first column R 1  and the battery cells in the second column R 2  may be aligned in a diagonal direction, e.g., at an acute angle, based on a main flow path D formed at the center of the battery pack. For example, the battery cells  10  in the first column R 1  and the battery cells  10  in the second column R 2  may be diagonally aligned at an acute angle to the main flow path D. The battery cells  10  in the first column R 1  and the battery cells in the second column R 2  may be symmetrically aligned with respect to the main flow path D. 
     The spacers  131  and  132  may be aligned between the neighboring battery cells  10 . The spacers  131  and  132  may include first spacers  131  and second spacers  132  protruding in an upward direction and a downward direction of the battery pack in which the first spacers and second spacers face each other. For example, the first spacers  131  may extend in the upward direction from a first position P 1  (corresponding to a bottom position), and the second spacers  132  may extend in the downward direction from a second position P 2  (corresponding to a top position). The first and second spacers  131  and  132  may interlock with one another in a comb form and may be alternately formed. 
     The first and second spacers  131  and  132  may extend from the first position P 1  and the second position P 2 , and the first position P 1  and the second position P 2  may respectively correspond to the first case  110  and a second case  120 , which may be coupled to each other in the upward direction and downward direction in which the first spacers and second spacers face each other. The first and second spacers  131  and  132  may be respectively formed in the first case  110  and the second case  120 . The first spacers  131  may protrude in the upward direction toward the second case  120  from the first case  110 , and the second spacers  132  may protrude in the downward direction toward the first case  110  from the second case  120 . 
     The first spacers  131  may include a plurality of unit members  131   a  aligned between a pair of neighboring battery cells  10  in a diagonal direction. Similarly, the second spacers  132  may include a plurality of unit members  132   a  aligned between a pair of neighboring battery cells  10  in a diagonal direction. The unit members  131   a  and  132   a  of the first and second spacers  131  and  132  may have substantially the same pole shape. The phrase “pole shape” refers to an elongated shape extending in one direction (a vertical direction), and a cross-section of the pole shape may have various shapes such as a circular, oval, rectangular, or polygonal shape. 
     The first and second spacers  131  and  132  may interlock with one another in a comb form. Gap flow paths G may be formed between the first and second spacers  131  and  132 , which may interlock with one another. As shown in  FIG. 5 , the gap flow paths G may be formed in a zigzag pattern reciprocating along the upward and downward directions. 
     Referring to the attached drawings, the first spacers  131  may extend toward the second case  120 , which may be disposed at a top portion of the battery pack, from the first case  110 , and may not contact the second case  120  (for example, the first spacers  131  may extend toward the second position P 2 , and may not reach the second position P 2 ). Similarly, the second spacers  132  may extend toward the first case  110 , which may be disposed at a bottom portion of the battery pack, from the second case  120 , and may not contact the first case  110  (for example, the second spacers  132  may extend toward the first position P 1 , and may not reach the first position P 1 ). 
     The first spacers  131  may extend in the upward direction from the first case  110 , and end portions of the first spacers  131  may be not contact the second face  120  and may be separated from the second case  120 . The second spacers  132  may extend in the downward direction from the second case  120 , and end portions of the second spacers  132  may not contact the first case  110  and may be separated from the first case  110 . The end portions of the first spacers  131  and the end portions of the second spacers  132  may form the gap flow paths G between the second case  120  and the first case  110 , which respectively may face the end portions of the first spacers  131  and the end portions of the second spacers  132 . 
     The first and second spacers  131  and  132  may extend in the upward and downward directions, in which the first spacers and second spacers face each other, to locations where the end portions of the first spacers  131  overlap the end portions of the second spacers  132 . The first and second spacers  131  and  132  may extend to the locations where the end portions of the first spacers  131  overlap the end portions of the second spacers  132  or may extend further from the locations where the end portions of the first spacers  131  overlap the end portions of the second spacers  132 . As described below, this structure may generate flow reciprocating in a zigzag pattern along the upward and downward directions, for example, due to the first and second spacers  131  and  132 , and may be configured to block the shortest flow path that passes straight between the first and second spacers  131  and  132  and increase the length of a heat dissipation path by forming a flow path reciprocating in a zigzag pattern. 
     In short, it may be advantageous that the first and second spacers  131  and  132  extend in the upward and downward directions, in which the first spacers and second spacers face each other, and overlap one another, and do not contact the second case  120  and the first case  110 , which respectively face the end portions of the first spacers  131  and the end portions of the second spacers  132 . 
     The gap flow paths G may be defined by the first and second spacers  131  and  132 , which may interlock with each other, and may have a zigzag pattern reciprocating along the upward and downward directions. The gap flow paths G may be formed when a space between the first spacers  131  and the second case  120 , a space between the first and second spacers  131  and  132 , which may interlock with each other, and a space between the second spacers  132  and the first case  110  are continuously connected, e.g., the gap flow paths may include a space between the first spacers and the second case, a space between the first and second spacers interlocking with one another in a comb form, and a space between the second spacers and the first case. As a space between the first spacers  131  and the second case  120 , a space between the first and second spacers  131  and  132 , and a space between the second spacers  132  and the first case  110  are interconnected, the gap flow paths G may have a reciprocating zigzag pattern. 
     As shown in  FIG. 4 , air that forcibly flows, for example, due to a fluid machine M, may pass through the gap flow paths G, and the battery cells  10  may dissipate heat. In one exemplary embodiment, the fluid machine M may be of a suction type which generates air flow through a suction force providing negative pressure. In an embodiment, the fluid machine M may be of a blow type which forces air flow by providing positive pressure. 
     A pressure difference generated by the fluid machine M may generate air flow in the main flow path D and may generate air flow in the gap flow paths G continuously connected to the main flow path D. For example, the fluid machine M may be formed on the main flow path D. The main flow path D may be formed along a front-rear direction of the battery pack, and the fluid machine M may be arranged on a front side of the first case  110 . The pressure difference generated by the fluid machine M may absorb air flow through the main flow path D and may generate air flow of the gap flow paths G continuously connected to the main flow path D. The air flow through the gap flow paths G may have a zigzag pattern reciprocating along the upward and downward directions, for example, due to the first and second spacers  131  and  132 , which may interlock with one another in a comb form. As the air flow through the gap flow paths G has the zigzag pattern reciprocating along the upward and downward directions, lengths of the gap flow paths G exchanging heat with the battery cells  10  may be doubled. If the gap flow paths G are not formed in the zigzag pattern and have the shortest distance by crossing the battery cells  10 , the lengths of the gap flow paths G may not be great enough to exchange heat with the battery cells  10 . 
     Referring to  FIG. 4 , the battery cells  10  in the first and second columns R 1  and R 2  may be diagonally aligned at a predetermined acute angle to the main flow path D by interposing the main flow path D therebetween. According to operations of the fluid machine M formed on the main flow path D, air flow may be generated in the main flow path D and in the gap flow paths G continuously connected to the main flow path D. As the battery cells  10  in the first and second columns R 1  and R 2  are diagonally aligned at a predetermined acute angle to the main flow path D, the fluid resistance between the main flow path D and the gap flow paths G may decrease, and pressure loss may also decrease, and the operation power of the fluid machine M for generating the same amount of flux may decrease. 
     In one exemplary embodiment, the battery cells  10  may be aligned in the first and second columns R 1  and R 2 . In an exemplary embodiment, the battery cells  10  may be aligned in a single column on any one of a left or right side of the main flow path D, or may be aligned in four columns on both the left and right sides of the main flow path D. 
     In one exemplary embodiment, the battery cells  10  may be diagonally aligned with respect to the main flow path D. In an exemplary embodiment, the battery cells  10  may be vertically aligned with respect to the main flow path D. According to the exemplary embodiment described with reference to  FIG. 4 , if the gap flow paths G between the battery cells  10  are diagonally formed with respect to the main flow path D, the gap flow paths G between the battery cells  10  may be vertically aligned with respect to the main flow path D. The first and second spacers  131  and  132 , which may be disposed between a pair of neighboring battery cells  10 , may interlock with one another in a comb form and may induce air circulating in a zigzag pattern reciprocating along the upward and downward directions. 
     Referring to  FIG. 2 , the battery pack may include the battery cells  10  disposed between the first case  110  and the second case  120 , and the first case  110  and the second case  120  coupled in the upward and downward directions, in which the first spacers and second spacers face each other. The first and second spacers  131  and  132  may be respectively formed in the first case  110  and the second case  120 . 
     The first case  110  and the second case  120  may have a space for housing the battery cells  10 . The first case  110  and the second case  120  may be asymmetrically formed. The first case  110  may include a bottom portion  110   b  and side portions  110   s  to form a housing space, and the second case  120  disposed on the first case  110  may form a ceiling of the housing space. The first case  110  may have a hexahedron-box shape having an open upper portion, and the second case  120  may have a flat-panel shape. The second case  120  may be disposed on the first case  110  to cover the open upper portion of the first case  110 . 
     An opening  110 ′ may be formed in the upper portion of the first case  110  to insert the battery cells  10  into the first case  110 , and the second case  120  may be assembled on the battery cells  10 , which may be housed in the first case  110 , through the opening  110 ′. Therefore, the open upper portion of the first case  110  may not mean that the first case  110  does not have an upper structure, but may mean that the opening  110 ′ for assembling the battery cells  10  may be formed. 
     In the first case  110 , an opening  110 ″ corresponding to the main flow path D may be formed. The opening  110 ″ may be covered by the second case  20 . The openings  110 ′ and  110 ″ may be provided for convenience of assembly of the battery cells  10  and the fluid machine M. The first case  110  may have a circuit housing portion  110   c  for housing a protection circuit module. The second case  120  may be disposed on the circuit housing portion  110   c , in which the protection circuit module may be housed. 
     At least one of the first case  110  and the second case  120  may have through holes, for example, first and second through holes  1101  and  1102  for inducing low-temperature air and discharging heated air. For example, the first through hole  1101  and the second through hole  1102  may be formed in the side portions  110   s  of the first case  110 . The first through hole  1101  may be formed to be adjacent to the fluid machine M to be connected to the main flow path D. The first through hole  1101  may be fluidally connected to the fluid machine M. For example, the fluid machine M may be mounted in the first through hole  1101 , and the first through hole  1101  may forcibly discharge inner air to the outside, for example, due to a pressure difference generated by the fluid machine M. The second through hole  1102  may be formed to be adjacent to the battery cells  10  to be connected to the gap flow paths G. 
     In one exemplary embodiment, the fluid machine M may be of a suction type which may generate air flow through a suction force. The low-temperature air coming through the second through hole  1102  may be heated when passing through the gap flow paths G between the battery cells  10  and may be discharged to the outside by sequentially passing through the main flow path D and the first through hole  1101 . The second through hole  1102  may function as an inlet for receiving the low-temperature air, and the first through hole  1101  may function as an outlet for discharging the heated air. 
     For example, when the main flow path D is formed along a front-rear direction of the battery pack, the first through hole  1101  may be formed in the side portion  110 s on the front of the battery pack, and when the battery cells  10  in the first and second columns R 1  and R 2  are aligned on the left and right sides of the battery pack, the second through hole  1102  may be formed in the side portions  110   s  on the left and right sides of the battery pack. 
     Openings  1201  may be formed in the second case  1120  to expose upper portions of the battery cells  10 . For example, the openings  1201  of the second case  120  may be formed in a diagonal direction such that the openings  1201  may be parallel to the battery cells  10  at locations corresponding to the battery cells  10 . For example, a bus bar for electrically connecting the battery cells  10  or wires for obtaining or transmitting state information of the battery cells  10  may be arranged on the upper portions of the battery cells  10  which may be exposed by the openings  1201  and may be connected to terminals formed on the upper portions of the battery cells  10 . 
     The openings  1201  formed in the second case  120  may function as outlets for discharging the heated air to the outside. For example, flow of the air, which may be heated while passing through the gap flow paths G between the battery cells  10 , may be elevated, for example, due to buoyancy, and the air may be discharged to the outside via the openings  1201  of the second case  120 . 
     According to one or more exemplary embodiments, a battery pack that may have improved heat dissipation efficiency is provided. As heat dissipation paths having a zigzag pattern reciprocating between the neighboring battery cells  10  may be formed, heat dissipation paths having enough lengths may be formed. As the air flowing in the heat dissipation paths and heat in the battery cells  10  are sufficiently exchanged, the heat dissipation efficiency of the battery cells  10  may be improved. 
     As the battery cells  10  may be aligned in a diagonal direction with respect to the main flow path D connected to a fluid machine M, pressure loss between the main flow path D and the gap flow paths G disposed between the battery cells  10  may decrease, and operation, e.g., driving, power of the fluid machine M for generating air flow having the same flux may be decreased. 
     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 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.