Patent Publication Number: US-2022231366-A1

Title: Battery Pack

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/624,707, filed on Dec. 19, 2019, which is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/KR2018/013741 filed Nov. 12, 2018, which claims priority to Korean Patent Application No. 10-2017-0164084 filed on Dec. 1, 2017 in the Republic of Korea, the disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a battery pack, and more particularly, to a battery pack capable of improving heat dissipation efficiency. 
     BACKGROUND ART 
     As technology development and demand for a mobile device have increased, demand for a secondary battery as an energy source has rapidly increased. Conventionally, a nickel-cadmium battery or a hydrogen ion battery has been used as the secondary battery. However, a lithium secondary battery is recently widely used because charging and discharging is free due to rare memory effect in comparison with a nickel-based secondary battery, a self-discharge rate is very low, and an energy density is high. 
     The lithium secondary battery mainly uses a lithium oxide and a carbonaceous material as a positive electrode active material and a negative electrode active material, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate, respectively coated with the positive electrode active material and the negative electrode active material, are arranged with a separator therebetween, and an outer member, that is a battery case, which seals and receives the electrode assembly together with an electrolyte solution. 
     The lithium secondary battery includes a positive electrode, a negative electrode, and a separator interposed therebetween and an electrolyte. Depending on which material is used for the positive electrode active material and the negative electrode active material, the lithium secondary battery is classified into a lithium ion battery (LIB) and a polymer lithium ion battery (PLIB). Generally, an electrode of the lithium secondary battery may be prepared by applying the positive or negative electrode active material to a current collector made of aluminum or copper sheet, mesh, film, foil, or the like and then drying the same. 
       FIG. 1  is a schematic exploded perspective view showing a conventional battery pack,  FIG. 2  is a schematic perspective view showing the conventional battery pack, and  FIG. 3  is a schematic cross-sectioned view, taken along the line A-A′ of  FIG. 2 . 
     Referring to  FIGS. 1 to 3 , a conventional battery pack  1  includes a battery module  2 . In the battery module  2 , based on  FIG. 1 , a thermal pad  4  and a heatsink  5  are sequentially coupled to a bottom portion  3  to emit heat generated from the battery module  2 . However, a region of the battery cell where heat is generated most is an electrode lead or a bus bar  6  directly connected to the electrode lead, rather than a bottom surface of the battery cell. Thus, even though the thermal pad  4  and the heatsink  5  are coupled to the bottom portion  3  of the battery module  2  where battery cells are stacked, the heat dissipation efficiency is not high. In  FIGS. 1 and 2 , the reference sign  7  designates a lower tray. 
     Also, as in  FIG. 3 , the thermal pad  4  and the heatsink  5  are coupled to the bottom portion  3  of the battery module  2 . Thus, the total height of the battery pack  1  accommodating the plurality of the battery modules  2  is increased as much as the thickness of the thermal pad  4  and the heatsink  5 . 
     In addition, as in  FIG. 1 , the thermal pad  4  and the heatsink  5  are manufactured to have a size corresponding to the total size of the bottom portion  3  of the battery module  2 . Thus, the thermal pad  4  and the heatsink  5  should have a large area, which increases the cost. 
     SUMMARY 
     Technical Problem 
     The present disclosure is directed to providing a battery pack, which may improve the heat dissipation efficiency through a structural change. 
     Also, the present disclosure is directed to providing a battery pack, which may have a reduced total thickness. 
     In addition, the present disclosure is directed to providing a battery pack, which may require a reduced cost to manufacture a heat dissipation member. 
     Technical Solution 
     In one aspect of the present disclosure, there is provided a battery pack, comprising: a battery module having a plurality of battery cells; and a heat dissipation member provided in contact with a bus bar at a side surface of the battery module where electrode leads of the plurality of battery cells and the bus bar coupled to the electrode leads are disposed 
     Also, the battery module may include a plurality of battery modules, each battery module having a plurality of battery cells and a side surface where electrode leads of the plurality of battery cells and the bus bar coupled to the electrode leads are disposed. The plurality of battery modules may be provided in a single layer and arranged in at least one row or column. 
     In addition, the heat dissipation member may have a cavity formed therein whereby the plurality of battery modules are disposed in the cavity, and the heat dissipation member surrounds the side surface of each of the plurality of battery modules. 
     Also, the heat dissipation member may have a band shape to surround rims of the plurality of battery modules, and the heat dissipation member may be provided incontact with the bus bar. 
     In addition, the heat dissipation member may include: a thermal pad coupled to the bus bar at the side surface of the battery module, and a heatsink coupled to the thermal pad. 
     Also, the heat sink may be configured to form a flow path so that a fluid for cooling flows therethrough. 
     In addition, the heat dissipation member may have a height corresponding to a height of the side surface of the battery module. 
     Meanwhile, in another aspect of the present disclosure, there is also provided a vehicle, comprising the battery pack of any of the embodiments described herein. 
     In another aspect of the present disclosure, there is provided a heat dissipation apparatus for dissipating heat generated by a battery module having a plurality of cells. The heat dissipation apparatus includes a heat dissipation member provided in contact with a bus bar of the battery module at a side surface of the battery module where electrode leads of the plurality of battery cells and the bus bar coupled to the electrode leads are disposed. 
     Advantageous Effects 
     In the embodiments of the present disclosure, since the heat dissipation member is in direct or indirect contact with an electrode lead or a bus bar directly connected to the electrode lead where heat is emitted relatively greater, rather than to a bottom portion of the battery module where heat is emitted relatively smaller, it is possible to improve the heat dissipation efficiency. 
     Also, since the thermal pad and the heatsink are coupled to the side surface of the battery module, rather than to the bottom portion of the battery module, it is possible to reduce the total height of the battery pack. 
     In addition, since the heat dissipation member is coupled to the battery module only at the side surface, the total area of the heat dissipation member is decreased, thereby reducing the cost of manufacturing the heat dissipation member. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic exploded perspective view showing a conventional battery pack. 
         FIG. 2  is a schematic perspective view showing the conventional battery pack. 
         FIG. 3  is a schematic cross-sectioned view, taken along the line A-A′ of  FIG. 2 . 
         FIG. 4  is an exploded perspective view showing a battery pack according to the first embodiment of the present disclosure. 
         FIG. 5  is a perspective view showing the battery pack according to the first embodiment of the present disclosure. 
         FIG. 6  is a schematic cross-sectioned view, taken along the line B-B′ of  FIG. 5 . 
         FIG. 7  is a schematic perspective view showing that a heat dissipation member is coupled to a side surface of a battery module, at the battery pack according to the first embodiment of the present disclosure. 
         FIG. 8  is a schematic cross-sectioned view, taken along the line C-C′ of  FIG. 7 . 
         FIG. 9  is a schematic perspective view showing that a heat dissipation member is coupled to a side surface of a battery module, at a battery pack according to the second embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the disclosure, so it should be understood that other equivalents and modifications could be made thereto without departing from the scope of the disclosure. 
     In the drawings, the size of each element or a specific part of the element may be exaggerated, omitted, or schematically illustrated for convenience and clarity of a description. Thus, the size of each element does not entirely reflect the actual size of the element. A detailed description of well-known functions or elements associated with the present disclosure will be omitted if it unnecessarily obscures the subject matter of the present disclosure. 
     The term, ‘combine’ or ‘connect’ as used herein, may refer not only to a case where one member and another member are directly combined or directly connected but also a case where one member is indirectly combined with another member via a connecting member or is indirectly connected. 
       FIG. 4  is an exploded perspective view showing a battery pack according to the first embodiment of the present disclosure,  FIG. 5  is a perspective view showing the battery pack according to the first embodiment of the present disclosure,  FIG. 6  is a schematic cross-sectioned view, taken along the line B-B′ of  FIG. 5 ,  FIG. 7  is a schematic perspective view showing that a heat dissipation member is coupled to a side surface of a battery module, at the battery pack according to the first embodiment of the present disclosure, and  FIG. 8  is a schematic cross-sectioned view, taken along the line C-C′ of  FIG. 7 . 
     Referring to  FIGS. 4 to 8 , a battery pack  10  according to the first embodiment of the present disclosure includes a battery module  100  and a heat dissipation member  200 . In  FIGS. 4 and 5 , the reference sign  300  designates a lower tray. 
     In the battery pack  10 , a plurality of battery modules  100  may be stacked or arranged in various ways. However, for convenience of explanation, it will be assumed that the plurality of battery modules  100  are provided in a single layer and arranged in at least one row or column. Here, the ‘row’ means the X direction based on  FIG. 4 , and the ‘column’ means the Y direction based on  FIG. 4 . In the first embodiment, the battery modules  100  are arranged in one row and six columns If the plurality of battery modules  100  are provided in a single layer as described above, the battery modules  100  may be easily disposed in a space with a limited height, such as an underfloor of an electric vehicle or the like. However, the use of the battery pack  10  according to the first embodiment of the present disclosure is not limited to a vehicle or the like. 
     The battery pack  10  may include an upper case (not shown) and a pack cover (not shown), and the upper case may be coupled to the pack cover to accommodate and protect the plurality of the battery modules  100 . The upper case and the pack cover may accommodate one battery module  100  or a plurality of battery modules  100 . That is, at least one battery module  100  is arranged inside the upper case and the pack cover so that the upper case and the pack cover surround and protect the battery module  100 . Namely, the upper case and the pack cover entirely enclose the battery module  100 , thereby protecting the battery module  100  against external vibration or shock. The upper case and the pack cover may be shaped corresponding to the shape of the battery module  100 . For example, if the entire shape of the battery modules  100  arranged in a single layer is a hexahedron shape, the upper case and the pack cover may be provided in a hexahedron shape to correspond thereto. The upper case and the pack cover may be fabricated, for example, by bending a metal plate, and thus the upper case and the pack cover may be fabricated in an integrated form. Here, if the upper case and the pack cover are integrally fabricated, the coupling process may be performed in a simple and convenient way. Alternatively, the upper case and the pack cover may be fabricated separately and coupled together using various methods such as welding, riveting, bolt, bolting, pin coupling, bracketing, moment bonding or the like. In addition, the battery pack  10  may include various devices for controlling charge and discharge of the battery module  100 , such as a battery management system (BMS), a current sensor, a fuse, and the like. 
     The battery module  100  includes a plurality of battery cells  110 . The battery cell  110  may be configured so that a plurality of unit cells, in each of which a positive electrode plate, a separator and a negative electrode plate are arranged in order, or a plurality of bi-cells, in each of which a positive electrode plate, a separator, a negative electrode plate, a separator, a positive electrode plate, a separator and a negative electrode plate are arranged in order, are stacked suitable for a battery capacity. In addition, the battery cell  110  (see  FIG. 6 ) may include an electrode lead  111  (see  FIG. 8 ). The electrode lead  111  is a kind of terminal exposed to the outside and connected to an external device and may be made of a conductive material. Here, the electrode lead  111  may be electrically coupled to a bus bar  120  (see  FIG. 8 ).  FIG. 4  schematically shows that the bus bar  120  is coupled to the electrode lead  111 , and the bus bar  120  made of a conductive metal may have a frame function together. Alternatively, a frame made of a metal may be coupled to the bus bar  120  and the heat dissipation member  200  may be coupled to the frame such that the heat dissipation member  200  is indirectly coupled to the bus bar  120  by means of the frame. The electrode lead  111  may include a positive electrode lead and a negative electrode lead. The positive electrode lead and the negative electrode lead may be disposed at opposite sides of the battery cell  110  in the longitudinal direction, or the positive electrode lead and the negative electrode lead may be disposed at the same side the battery cell  110  in the longitudinal direction. Meanwhile, the battery module  100  may include a plurality of cartridges for accommodating the battery cells  110 . Each cartridge may be fabricated by injection-molding plastic, and a plurality of cartridges having an accommodation portion for accommodating the battery cell  110  may be stacked. A cartridge assembly in which a plurality of cartridges are stacked may include a connector element or a terminal element. The connector element may include various types of electrical connecting components or connecting members for connecting to, for example, a battery management system (BMS) (not shown) capable of providing data on voltage or temperature of the battery cells  110 . In addition, the terminal element includes a positive electrode terminal and a negative electrode terminal as main terminals connected to the battery cell  110 , and the terminal element may have a terminal bolt to be electrically connected to the outside. 
     Referring to  FIGS. 4, 5 and 7 , the heat dissipation member  200  is in contact with the bus bar  120  provided to the battery module  100  at a side surface of the battery module  100 . The side surface of the battery module  100  means a portion of the battery module  100 , where the electrode lead  111  protrudes and is coupled to the bus bar  120 , namely where the electrode lead  111  is coupled to the bus bar  120 , when the battery module  100  is arranged as in  FIG. 4 . 
     As shown in  FIG. 4 , the heat dissipation member  200  may have a hollow  230  formed therein, and the battery modules  100  may be disposed in the hollow  230  of the heat dissipation member  200 . Also, the heat dissipation member  200  having the hollow  230  may be formed to surround the side surfaces of the plurality of battery modules  100  (see  FIGS. 5 and 7 ). In addition, the heat dissipation member  200  may have a band shape as shown in  FIG. 4 . If the heat dissipation member  200  is formed in a band shape as described above, the heat dissipation member  200  contacts the bus bar  120  while surrounding the entire rim of the plurality of battery modules  100 , and thus the heat generated from the battery cells  110  may be directly emitted by the heat dissipation member  200  through the electrode leads  111  and the bus bar  120 . 
     The heat dissipation member  200  may include a thermal pad  210  and a heatsink  220 . The thermal pad  210  may be coupled to the bus bar  120  at the side surfaces of the plurality of battery modules  100 , and the heatsink  220  may be coupled to the thermal pad  210  (see  FIG. 8 ). Due to the thermal pad  210  coupled to the bus bar  120  and the heatsink  220  coupled to the thermal pad  210 , the heat generated within the battery cells  110  may be directly emitted through the bus bar  120 . 
     The heat dissipation member  200  may have a height corresponding to the height of the side surface of the battery module  100 . That is, the height of the side surface of the battery module  100  and the height of the bus bar  120  may be substantially the same, and the height of the heat dissipation member  200 , namely the thermal pad  210  and the heatsink  220 , may be substantially equal to the height of the bus bar  120 . However, the present disclosure is not necessarily limited thereto, and an appropriate height may be selected as necessary. 
     The heatsink  220  of the heat dissipation member  200  may have a flow path  221  through which a fluid for cooling flows, as shown in  FIG. 8 . In addition, referring to  FIG. 4 , the heatsink  220  may have an inlet  222  through which the fluid flows in and an outlet  223  through which the fluid flows out. The fluid introduced through the inlet  222  flows along the flow path  221  formed at the heatsink  220  and is discharged out through the outlet  223  (see the arrow L in  FIG. 7 ). While the fluid flows along the flow path  221 , heat is transferred to the thermal pad  210  coupled to the heatsink  220 . 
     As described above, the region of the battery cell  110  where heat is generated most is the electrode lead  111  or the bus bar  120  directly connected to the electrode lead  111 , rather than the bottom surface of the battery cell  110 . Thus, if the heat dissipation member  200  of the battery pack  10  according to the first embodiment of the present disclosure is coupled to the bus bar  120  at the side surfaces of the battery modules  100 , the heat dissipation efficiency is greatly enhanced, compared to the conventional case where the heat dissipation member  200  is coupled to the bottom portion of the battery module  100 . In addition, since the heat dissipation member  200  is formed in a band shape to contact only the side surface of the battery module  100 , the area of the heat dissipation member  200  is significantly reduced compared to the conventional heat dissipation member  200  that contacts the entire bottom of the battery module  100 , thereby reducing the manufacturing cost. Also, referring to  FIG. 6 , since the heat dissipation member  200  is not coupled to the bottom portion of the battery module  100  but is coupled to the side surface of the battery module  100 , the overall height of the battery pack  10  may be reduced compared to the conventional case of  FIG. 3 . 
     Hereinafter, the operations and effects of the battery pack  10  according to the first embodiment of the present disclosure will be described. 
     The plurality of battery modules  100  may be provided in a single layer and arranged in at least one row or column. At this time, the electrode lead  111  of the battery cell  110  and the bus bar  120  coupled to the electrode lead  111  are disposed at the side surface of the battery module  100 . The heat dissipation member  200  may include the thermal pad  210  and the heatsink  220 . The heat dissipation member  200  may have the hollow  230  formed therein and be formed in a band shape to surround the side surfaces of the battery modules  100 . In addition, the thermal pad  210  is in contact with each bus bar  120  located at the side surfaces of the battery modules  100 , and the heatsink  220  is coupled to the thermal pad  210 . The flow path  221  is formed inside the heatsink  220 , and the fluid exchanges heat with the thermal pad  210  while moving along the flow path  221  inside the heatsink  220 . As a result, the heat generated at the battery cell  110  may be emitted while moving to the thermal pad  210  and the heatsink  220  through the electrode lead  111  and the bus bar  120 . 
       FIG. 9  is a schematic perspective view showing that a heat dissipation member is coupled to a side surface of a battery module  100 , at a battery pack  10  according to the second embodiment of the present disclosure. 
     Hereinafter, the operations and effects of the battery pack  10  according to the second embodiment of the present disclosure will be described with reference to the accompanying drawings. Here, a feature already explained in relation to the battery pack  10  according to the first disclosure of the present disclosure will not be described in detail again. 
     In the second embodiment of the present disclosure, the battery modules  100  are arranged in a plurality of rows and a plurality of columns and coupled to the heat dissipation member  200 , different from the first embodiment where the battery modules are arranged in one row and a plurality of columns. 
     That is, even though the battery modules  100  are arranged in one row and six columns in the first embodiment, in the second embodiment, the battery modules  100  are arranged in two rows and six columns. Meanwhile, the number of rows and columns of the battery modules  100  may be varied, and in some cases, one battery module  100  arranged in one row and one column may be included in one battery pack  100 . 
     Referring to  FIG. 9 , the battery modules  100  are arranged in two rows and six columns In addition, the heat dissipation member  200  may be bent between the battery module  100  in the first row and the battery module  100  in the second row to contact both the battery module  100  in the first row and the battery module  100  in the second row. Here, the fluid introduced through the inlet  222  flows along the flow path  221  formed in the heatsink  220  and is discharged out through the outlet  223  (see the arrow M in  FIG. 9 ). Referring to  FIG. 9 , one heat dissipation member  200  is provided to surround both the battery module  100  in the first row and the battery module  100  in the second row. By doing so, the number of inlets  222  and outlets  223  may be reduced, compared to the case where two heat dissipation members  200  are provided to surround the battery module  100  in the first row and the battery module  100  in the second row individually. However, if necessary, two heat dissipation members  200  may be provided to surround the battery module  100  in the first row and the battery module  100  in the second row individually. 
     Meanwhile, a vehicle (not shown) according to an embodiment of the present disclosure may include the battery pack  10  described above, and the battery pack  10  may include the battery module  100 . In addition, the battery pack  10  according to the first and second embodiments of the present disclosure may be applied to the vehicle (not shown), for example a vehicle using electricity such as an electric vehicle or a hybrid electric vehicle. 
     The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure relates to a battery pack and is particularly applicable to an industry related to a secondary battery.