Patent Publication Number: US-11646463-B2

Title: Battery pack and electric vehicle

Description:
PRIORITY 
     The present application is a Continuation of U.S. application Ser. No. 16/428,357, filed on May 31, 2019, issued May 4, 2021, U.S. Pat. No. 10,998,589, which claims priority to C.N. Application No. CN201810614053.0 filed on Jun. 14, 2018, which are incorporated by reference herein in the entireties. 
    
    
     FIELD 
     The present disclosure relates to the technical field of batteries and in particular, to a battery pack and an electric vehicle. 
     BACKGROUND 
     The desired normal operating temperature of a battery in a battery pack is from 20° C. to 35° C. In a cold or hot environment, in order to ensure the normal service life of the battery, the battery pack must be provided with a thermal management to adjust the working temperature of the battery by means of heating or cooling. 
     In order to adjust the working temperature of the battery while the battery pack is in operation, a conventional battery pack commonly uses the following solutions: (1) providing a cooling plate inside the battery case; and (2) providing a cooling plate outside the battery case. 
     For the first solution in which the cooling plate is placed inside the battery case, the existing structure of the battery pack needs to be redesigned, and since the space inside the battery case is relatively tight, this greatly limits the design. At the same time, in the case where coolant leaks from the cooling plate in the battery pack in a long-term use, on the one hand, the coolant may enable a conductivity connection between the outer part of the battery and the metal parts of the case, thereby reducing the overall insulation resistance of the case; on the other hand, the coolant may also accelerate the corrosion process of the metal parts of the case, which poses a safety hazard. 
     For the second solution in which the cooling plate is placed outside the battery case, although it solves the problem of space utilization inside the case and the impact of the coolant leakage on the interior of the battery case, in the case that the battery pack is used in an electric vehicle, the cooling plate of the battery pack may be in direct contact with a mounting plate of the electric vehicle, since the temperature of the mounting plate is close to the temperature of the external environment of the electric vehicle, when the electric vehicle is in an extremely cold or hot environment, the mounting plate may exchange heat with the cooling plate, thereby reducing the cooling or heating efficiency of the cooling plate with respect to the interior of the battery case. 
     SUMMARY 
     In view of the problems discussed in the previous section, an object of the present disclosure is to provide a battery pack and an electric vehicle, where a bracket assembly of the battery pack separates the cooling plate from the mounting plate of the electric vehicle, thereby reducing the impact of the temperature of the mounting plate on the cooling plate. In this way, the cooling or heating efficiency of the cooling plate is improved. 
     In order to achieve the above objective, the present disclosure provides a battery pack for an electric vehicle, which can include a casing, a cooling plate located below the casing in a height direction, and a bracket assembly located below the cooling plate in a height direction and fixedly coupled to the casing, and the bracket assembly is used for a direct contact with a mounting plate of the electric vehicle. 
     The bracket assembly can include at least two longitudinal beams, which are arranged apart along a width direction; and at least two transverse beams, which are arranged apart along a length direction, and two transverse beam ends in the width direction of each transverse beams are respectively fixedly connected to a corresponding longitudinal beam. 
     The cooling plate can include a main body portion and a plurality of first mounting portions, wherein each of the first mounting portions is protrudingly formed from the main body portion. In some embodiments, each of the longitudinal beams can include a plurality of second mounting portions formed on a side of the longitudinal beam facing the cooling plate, each of the second mounting portions engages a corresponding first mounting portion of the cooling plate and is fixedly connected to the corresponding first mounting portion. 
     The cooling plate can further include a plurality of first engaging portions formed on the side of the cooling plate facing the bracket assembly and arranged apart along the width direction; each of the transverse beams can further include a plurality of second engaging portions formed on the side of the transverse beams facing the cooling plate and arranged apart in the width direction, and each of the second engaging portions has a protrusion recess engagement with a corresponding one of the first engaging portions. 
     In some embodiments, each of the first engaging portions of the cooling plate can form a U-shaped structure. In some embodiments, the plurality of second engaging portions of the beams can form a serrated structure. 
     In some embodiments, each of the longitudinal beams can further include a plurality of third mounting portions formed on the side of the longitudinal beam facing the cooling plate and arranged apart in the length direction, and each of the third mounting portions is fixedly connected to a transverse beam end of a corresponding transverse beam. 
     In some embodiments, the bracket assembly can further include a protective beam fixedly connected to the longitudinal beam ends of each longitudinal beam in the length direction for protecting the cooling plate in the length direction. 
     In some embodiments, each of the longitudinal beams can further include a fourth mounting portion formed on the side of the longitudinal beam end facing the cooling plate and fixedly connected to the protective beam. 
     The protective beam can include a flat plate portion, which is arranged side by side with the at least two transverse beams; and a side plate portion, which protrudes from the flat plate portion in the height direction and is located on one side of the longitudinal direction of the cooling plate, and protects the cooling plate in the longitudinal direction. 
     In some embodiments, each of the longitudinal beams can further include a supporting member, which is formed on a side of the width direction of the longitudinal beam and extends in the width direction; and a mounting portion, which is formed on the other side in the width direction of a longitudinal beam and extends in the width direction. 
     The present disclosure also provides an electric vehicle including the battery pack, which includes a casing wherein a battery is placed, a cooling plate located below the casing in a height direction, and a bracket assembly located below the cooling plate in the height direction and fixedly connected to the casing, and the bracket assembly is used for a direct contact with a mounting plate of the electric vehicle. 
     Also disclosed is a method for regulating the temperature of a battery in a battery pack of an electric vehicle, the method includes providing a cooling plate in a direct contact with a battery casing in the battery pack and a bracket assembly providing separation between the cooling plate and a mounting plate of the electric vehicle, monitoring the working temperature of the battery in the battery casing, and adjusting the working temperature of the battery with the cooling plate, wherein the bracket assembly reduces thermal communication between the mounting plate and the cooling plate, thereby increasing the efficiency of the regulation of temperature of the battery. 
     In some embodiments, the beneficial effects of the present disclosure can include, but not limited to: the bracket assembly separates the cooling plate from the mounting plate of the electric vehicle, thereby reducing the impact of the temperature of the mounting plate on the cooling plate. In this way, the cooling or heating efficiency of the cooling plate is improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view of a battery pack, according to some embodiments of the present disclosure; 
         FIG.  2    is an close-up view of  FIG.  1   , according to some embodiments of the present disclosure; 
         FIG.  3    is an assembled view of a cooling plate, a bracket assembly, and a thermal pad, according to some embodiments of the present disclosure; 
         FIG.  4    is a disassembled view of  FIG.  3   , according to some embodiments of the present disclosure; 
         FIG.  5    is a back view of the cooling plate, according to some embodiments of the present disclosure; 
         FIG.  6    is a top view of the longitudinal beams of the bracket assembly, according to some embodiments of the present disclosure; 
         FIG.  7    is a back view of the longitudinal beams of the bracket assembly, according to some embodiments of the present disclosure; 
         FIG.  8    is a top view of the transverse beams of the bracket assembly, according to some embodiments of the present disclosure; 
         FIG.  9    is a back view of the transverse beams of the bracket assembly, according to some embodiments of the present disclosure; and 
         FIG.  10    is a perspective view of the protective beam of the bracket assembly, according to some embodiments of the present disclosure. 
     
    
    
     DESCRIPTION 
     The battery pack and electric vehicle according to the present disclosure will be further described in detail with reference to the accompanying drawings. 
     The elements in the figures are described in the following:
           1 : casing     11 : the seventh mounting hole     2 : cooling plate     21 : main body portion     22 : the first mounting portion     221 : the first mounting hole     23 : the first engaging portion     24 : the extending portion     3 : bracket assembly     31 : longitudinal beam     311 : longitudinal beam end     312 : the second mounting portion     3121 : the second mounting hole     313 : the third mounting portion     3131 : the third mounting hole     314 : the fourth mounting portion     3141 : the fourth mounting hole     315 : supporting member     316 : mounting member     3161 : connecting hole     317 : fixing hole     32 : transverse beam     321 : transverse beam end     3211 : the fifth mounting hole     322 : the second engaging portion     33 : protective beam     331 : the sixth mounting hole     332 : flat plate portion     333 : side plate portion     4 : thermal pad   S: fastener   W: the width direction   L: the length direction   H: the height direction       

     Disclosed herein is a battery pack design which utilizes a bracket assembly to separate a cooling plate for the battery casing from the mounting plate of an electric vehicle, the bracket assembly can also ensure the whole battery pack is fastened onto the mounting plate. As a result, the battery casing and the cooling plate are isolated from the rest of the electric vehicle specifically from the mounting plate, which prevents the influence of external temperature on the cooling plate and leads to a better temperature control over the battery casing. 
     In reference to  FIGS.  1  and  2   , an electric vehicle according to the present disclosure can include a mounting plate (not shown) and a battery pack. The mounting plate can be used to mount the battery pack and make direct contact with the battery pack. 
     In reference to  FIGS.  1  and  2   , the battery pack can include a casing  1  in which a battery (not shown) is placed, a cooling plate  2  located below the casing  1  in the height direction H, and a bracket assembly  3  located below the cooling plate  2  in the height direction H and fixedly connected to the casing  1 . In addition, the bracket assembly  3  is in a direct contact with a mounting plate. Since the bracket assembly  3  of the battery pack separates the cooling plate  2  from the mounting plate, the cooling plate  2  does not directly exchange heat with the mounting plate, thereby reducing impact of the temperature of the mounting plate (especially when the electric vehicle is in an extremely cold or hot environment) on the cooling plate  2 , and improving the cooling or heating efficiency of the cooling plate  2  with respect to the battery inside the casing  1 . 
     The type of battery can include, but is not limited to, lithium ion battery, aluminum ion battery, carbon battery, flow battery, lead-acid battery, glass battery, magnesium ion battery, metal air battery, molten salt battery, nickel cadmium battery, nickel hydrogen battery, nickel iron battery, nickel metal hydride battery, nickel zinc battery, organic radical battery, polymer-based battery, fuel cell, lithium sulfur battery, sodium ion battery, sodium sulfur battery, and zinc ion battery. In some embodiments, the battery is a lithium ion battery. 
     In reference to  FIG.  2   , the casing  1 , the cooling plate  2 , and the bracket assembly  3  are each a separate component. Accordingly, in the case where the cooling plate  2  fails, the cooling plate  2  can be replaced at any time. 
     In the process of using the battery pack, in order to achieve the adjustment of the cooling plate  2  on the operating temperature of the battery, the cooling plate  2  generally has a cooling liquid circulating therein, and the cooling liquid can be heated or stopped being heated in order to adjust the temperature, or the cooling plate  2  may be provided with heating membranes for temperature adjustment. 
     In reference to  FIGS.  1  and  2   , a plurality of the seventh mounting holes  11  can be provided on the exterior of the casing  1  of the battery pack, and the bracket assembly  3  is fixedly connected to the casing  1  by the plurality of the seventh mounting holes  11  on the casing  1  through fasteners S. 
     In reference to  FIGS.  3  and  4   , the bracket assembly  3  can include at least two longitudinal beams  31 , which are arranged apart along a width direction W; and at least two transverse beams  32 , which are arranged apart along a length direction L. The two transverse beam ends  321  in the width direction W of each transverse beams  32  can be respectively fixedly connected to a corresponding a longitudinal beam  31 . Moreover, the longitudinal beams  31  and the transverse beams  32  each can be made from a metal material, such as stainless steel, aluminum or aluminum alloy, and the like. 
     Herein, the bracket assembly  3  can be made by interconnecting at least two longitudinal beams  31  and at least two transverse beams  32  so as to form a frame structure. The bracket assembly  3  with this frame structure can allow a space with air circulation between the cooling plate  2  and the mounting plate. Since the thermal conductivity of air is very low, this can further reduce the heat transfer efficiency between the mounting plate and the cooling plate  2 , and thus reduce the impact of the temperature of the mounting plate on the temperature of the coolant within the cooling plate  2 , thereby improving the cooling or heating efficiency of the cooling plate  2  on the battery. Moreover, the load-carrying capacity and impact resistance of such a frame structure are very high, and the structural strength of the entire battery pack is thus improved. During the process of installation and transportation of the battery pack, the bracket assembly  3  can directly resist the impact or collision from an external object (including from the mounting plate) on the cooling plate  2 , thereby avoiding a damage on the cooling plate  2  caused by an external force. In this way, the frame assembly  3  can provide a good protection for the cooling plate  2 . In addition, this frame structure may also help to save materials and thus greatly reduces the costs. 
     In reference to  FIGS.  2  through  4   , the number of the longitudinal beam  31  can be two. However, it is not limited thereto, and in order to further enhance the strength of the entire bracket assembly  3 , the number of the longitudinal beam  31  can be increased accordingly. 
     The bracket assembly  3  can be arranged below the cooling plate  2  for supporting and fixedly mounting the cooling plate  2 . In reference to  FIGS.  4  and  5   , the cooling plate  2  can have a main body portion  21  and a plurality of first mounting portions  22 , each of the first mounting portions  22  can be protrudingly formed from the main body portion  21 . In addition, in reference to  FIGS.  3 ,  4  and  6   , each of the longitudinal beams  31  can include a plurality of second mounting portions  312  formed on a side of the longitudinal beam  31  facing the cooling plate  2 , each of the second mounting portions  312  can engage a corresponding first mounting portion  22  of the cooling plate  2  and can be fixedly connected to the corresponding first mounting portion  22 . During the process when the cooling plate  2  and the bracket assembly  3  are assembled, the cooling plate  2  can be quickly positioned due to the cooperation relationship between the second mounting portions  312  and the corresponding first mounting portion  22 . In this way, the cooling plate  2  and the bracket assembly  3  can be quickly assembled together. 
     In order to control the overall size of the cooling plate  2  and the bracket assembly  3  as a whole in the height direction H, the second mounting portions  312  of the longitudinal beams  31  can have protrusion recess engagement therebetween. Specifically, each of the second mounting portions  312  can be a protruding portion, and accordingly, the corresponding first mounting portion  22  can be a groove. Alternatively, each of the second mounting portions  312  can be a groove (as shown in  FIGS.  4  and  6   ), and accordingly, the corresponding first mounting portion  22  can be a protruding portion (as shown in  FIGS.  4  and  5   ). 
     In reference to  FIGS.  4  and  5   , the first mounting portions  22  can be formed to protrude in the width direction W on both sides in the width direction W of the main body portion  21 , and the first mounting portions  22  on the same side in the width direction W of the main body portion  21  can be spaced apart. 
     In reference to  FIGS.  4  and  5   , the cooling plate  2  can further include an extending portion  24  formed on one side of the longitudinal direction L of the main body portion  21  and protruding in the width direction W from the main body portion  21 . The first mounting portion  22  can be formed at both ends of the width direction W of the extending portion  24  and protrude in the length direction L, and the second mounting portions  312  that is engaged with the first mounting portions  22  on the extending portion  24  can be formed on the longitudinal beam end  311  of each of the longitudinal beams  31 . 
     In reference to  FIG.  3   , the plurality of first mounting portions  22  of the cooling plate  2  can be fixedly connected to the second mounting portions  312  of each of the longitudinal beams  31  of the bracket assembly  3  through the fasteners S. More specifically, in reference to  FIGS.  4  and  5   , each of the first mounting portions  22  of the cooling plate  2  can be provided with a first mounting hole  221 . In reference to  FIGS.  6  and  7   , each of the second mounting portions  312  on one of the longitudinal beams  31  can be provided with a second mounting hole  3121 . When assembling the cooling plate  2  and the longitudinal beams  31 , each of the first mounting holes  221  of the cooling plate  2  and a corresponding second mounting hole  3112  on a longitudinal beam  31  can be vertically aligned in the height direction H and are provided for a corresponding fastener S to pass through such that the cooling plate  2  and the longitudinal beams  31  can be fixedly connected with each other. 
     In order to ensure the reliability of the connection between the cooling plate  2  and the casing  1 , the second mounting holes  3121  on the bracket assembly  3 , the first mounting holes  221  on the cooling plate  2 , and the corresponding seventh mounting holes  11  on the casing  1  can be fixedly connected together via the fasteners S. 
     In reference to  FIGS.  3  through  5   , due to the easy and simple operation of a protrusion recess engagement, the cooling plate  2  can be fixedly connected to the respective transverse beams  32  of the bracket assembly  3  through the protrusion recess engagement, so as to facilitate quick assembling of the cooling plate  2  and the bracket assembly  3 . Specifically, in reference to  FIG.  5   , the cooling plate  2  can further include a plurality of first engaging portions  23  formed on the side of the cooling plate  2  facing the bracket assembly  3  and arranged apart along the width direction W. In reference to  FIGS.  4 ,  8  and  9   , each of the transverse beams  32  can further include a plurality of second engaging portions  322  formed on the side of the transverse beams  32  facing the cooling plate  2  and arranged apart in the width direction W, and each of the second engaging portions  322  has a protrusion recess engagement with a corresponding one of the first engaging portions  24 . Herein, based on the protrusion recess engagement between each of the second engaging portions  322  on the transverse beams  32  and the corresponding one of the first engaging portions  23  on the cooling plate  2 , the relative movement of the cooling plate  2  and the transverse beams  32  in the width direction W is limited, such that the cooling plate  2  is firmly fixed to the bracket assembly  3 , and the bracket assembly  3  is fixedly connected to the casing  1 , thereby ensuring the reliable connection between the cooling plate  2  and the casing  1 . 
     Each of the first engaging portions  23  of the cooling plate  2  may be a protruding portion, accordingly, each of the second engaging portions  322  on one of the transverse beams  32  can be a recess or groove. Alternatively, each of the first engaging portions  23  of the cooling plate  2  may be a recess (as shown in  FIG.  5   ), accordingly, each of the second engaging portions  322  on one of the transverse beams  32  is a protruding portion (as shown in  FIG.  8   ). 
     In reference to  FIG.  5   , each of the first engaging portions  23  of the cooling plate  2  can be a U-shaped structure, and the plurality of first engaging portions  23  are gradually distributed from the inside towards the outside (that is, formed into a radiation-like structure). 
     In reference to  FIGS.  8  and  9   , the plurality of second engaging portions  322  of each of the transverse beams  32  can form a serrated structure, and symmetrically distributed. 
     In reference to  FIGS.  3 ,  4  and  6   , each of the longitudinal beams  31  can further include a plurality of third mounting portions  313  formed on the side of the longitudinal beam  31  facing the cooling plate  2  and arranged apart in the length direction L, and each of the third mounting portions  313  can be fixedly connected to a transverse beam end  321  of a corresponding transverse beam  32 . When assembling the at least two longitudinal beams  31  and the at least two transverse beams  32  of the bracket assembly  3 , the third mounting portions  313  of the longitudinal beams  31  can be used for quickly positioning the transverse beams  32 , so as to facilitate quickly assembling the longitudinal beams  31  and the plurality of transverse beams  32  into one unit. Specifically, each of the third mounting portions  313  of the longitudinal beams  31  may be a groove, and each of the third mounting portions  313  can receive and fixedly connect one transverse beam end  321  of a corresponding transverse beam  32 . In this way, the overall size of the cooling plate  2  and the bracket assembly  3  along the height direction H is reduced. 
     In reference to  FIG.  3   , each of the transverse beams  32  can be fixedly connected to the longitudinal beams  31  through the fasteners S. Specifically, in reference to  FIGS.  6  and  7   , each of the third mounting portions  313  of the longitudinal beams  31  can be provided with a third mounting hole  3131 . In reference to  FIGS.  8  and  9   , each of the transverse beam ends  321  of the transverse beams  32  can be provided with a fifth mounting hole  3211 . When the at least two longitudinal beams  31  and the at least two transverse beams  32  are assembled together, the fifth mounting holes  3211  of the respective transverse beams  32  can be vertically aligned with the third mounting holes  3131  of the corresponding longitudinal beams  31  in the height direction H, such that a fastener S can pass through these holes to fixedly connect the transverse beams  32  and the longitudinal beams  31 . 
     In reference to  FIGS.  3  and  4   , the bracket assembly  3  can further include a protective beam  33  fixedly connected to the longitudinal beam ends  311  of each longitudinal beam  31  in the length direction L for protecting the cooling plate  2  in the length direction L. The protective beam  33  can be made of a metal material such as stainless steel, aluminum or aluminum alloy. 
     The number of protective beam  33  can be one. When the battery pack is mounted on the mounting plate, one end of the battery pack provided with the protective beam  33  in the length direction L can be first placed on the mounting plate, and then the entire battery pack can be pushed into the mounting plate along the length direction L. In this way, based on the setting of the protective beam  33 , the present disclosure can prevent the cooling plate  2  from being damaged during the installation of the battery pack. 
     In order to quickly position the protective beam  33  so as to quickly mount the protective beam  33  on the longitudinal beam ends  311  of the longitudinal beams, in reference to  FIGS.  6  and  7   , each of the longitudinal beams  31  can further include a fourth mounting portion  314  formed on the side of the longitudinal beam end  311  facing the cooling plate  2  and fixedly connected to the protective beam  33 . Specifically, the fourth mounting portion  314  of each of the longitudinal beams  31  can be a recess or groove, and the fourth mounting portion  314  receives and fixedly connects with the protective beam  33 , thereby reducing the overall size of the cooling element  2  and the bracket assembly  3  in the height direction H. 
     It is further noted that the fourth mounting portions  314  on the same longitudinal beam  31  and the second mounting portions  312  that cooperate with the first mounting portions  22  on the extending portion  24  can be respectively disposed at the two longitudinal beam ends  311  in the length direction L of the longitudinal beams  31 . 
     The protective beam  33  can be fixedly connected to the longitudinal beam ends  311  of each longitudinal beam  31  through a fastener S. Specifically, in reference to  FIGS.  6  and  7   , the fourth mounting portions  314  of each of the longitudinal beams  31  can be provided with a fourth mounting hole  3141 . In reference to  FIG.  10   , the protective beam  33  can be provided with a sixth mounting hole  331 . When the protective beam  33  and the longitudinal beams  31  are assembled together, the sixth mounting holes  331  on the protective beam  33  and the fourth mounting hole  3141  on the corresponding longitudinal beam  31  can be vertically aligned in the height direction H, through which a fastener S passes through so as to fixedly connect the protective beam  33  and the longitudinal beams  31 . 
     In reference to  FIG.  10   , the protective beam  33  can include a flat plate portion  332 , which is arranged side by side with the at least two transverse beams  32 ; and a side plate portion  333 , which protrudes from the flat plate portion  333  in the height direction H and is located on one side of the longitudinal direction L of the cooling plate  2 , and protects the cooling plate  2  in the longitudinal direction L. After the assembly of the cooling plate  2  and the bracket assembly  3  is finished, in reference to  FIGS.  3  and  4   , the flat plate portion  332  of the protective beam  33  and the transverse beams  32  together can support the cooling plate  2  on the bottom, so as to enhance the overall structural strength of the bracket assembly  3  as a whole. The side plate portion  333  of the protective beam  33  is located on the side in length direction L of the cooling plate  2 , so that the side plate portion  333  can protect the cooling plate  2  in the length direction L. 
     In reference to  FIGS.  6  and  7   , each of the longitudinal beams  31  can further include a supporting member  315 , which is formed on a side of the width direction W of the longitudinal beam  31  and extends in the width direction W. The supporting member  315  of the longitudinal beams  31  can be bonded to the casing  1  through a structural adhesive, thereby improving the reliability of the connection between the cooling plate  2  and the casing  1 , and contributing to the improvement of the structural strength of the entire battery pack. 
     In reference to  FIGS.  6  and  7   , each of the longitudinal beams  31  can further include a mounting member  316 , which can be formed on the other side in the width direction W of a longitudinal beam  31  and extends in the width direction W. The mounting member  316  of each of the longitudinal beams  31  can be used in the connection and fixation between the battery pack and the electric vehicle. 
     Further in reference to  FIGS.  6  and  7   , the mounting member  316  of each of the side members  31  can be provided with a connecting hole  3161 . The connecting hole  3161  can be used for the fastener S to pass through so as to tightly lock the battery pack and the electric vehicle together. 
     In reference to  FIGS.  6  and  7   , each of the longitudinal beams  31  can be provided with a plurality of fixing holes  317  which are spaced apart in the length direction L, and each of the fixing holes  317  penetrates through the longitudinal beam  31  in the height direction H. The fixing holes  317  of the longitudinal beams  31  can be used to achieve the connection and fixation between the bracket assembly  3  and the casing  1  of the battery pack through the fastener S. 
     In order to quickly transfer the heat from the casing  1  of the battery pack to the cooling plate  2 , in reference to  FIGS.  2  to  4   , the battery pack may further include a thermal pad  4  disposed between the casing  1  and the cooling plate  2 . In addition, the number of the thermal pad  4  can be reasonably adjusted according to the needs of the battery pack. 
     In order to ensure the flatness of the bottom of the bracket assembly  3  so as to facilitate reliable installation of the battery pack on the electric vehicle, the distal end of each of the second mounting holes  3121  away from the cooling plate  2  may form a countersunk slot structure for receiving a corresponding fastener S, and the distal end of each fixing hole  317  away from the cooling plate  2  may also form a countersunk slot structure for receiving the corresponding fastener S, as shown in  FIG.  7   . 
     Finally, it is noted that the fixing holes  317  of the longitudinal beams  31  of the bracket assembly  3  and the corresponding seventh mounting holes  11  of the casing  1  can be fixedly connected together by the fasteners S, so as to achieve a first reliable connection between the bracket assembly  3  and the casing  1 . The first mounting holes  221  of the cooling plate  2 , the corresponding second mounting holes  3121  on the longitudinal beams  31  of the bracket assembly  3 , and the corresponding seventh mounting holes  11  of the casing  1  can be fixedly connected together by the fasteners S, so as to achieve a second reliable connection between the bracket assembly  3  and the casing  1 . The supporting members  315  of the longitudinal beams  31  of the bracket assembly  3  can be bonded to the casing  1  through the structural adhesive, so as to achieve a third reliable connection between the bracket assembly  3  and the casing  1 . In this way, it is ensured that there is a reliable connection between the bracket assembly  3  and the casing  1 . In addition, since the bracket assembly  3  can support and fix the cooling plate  2 , the reliability of the connection between the cooling plate  2  and the casing  1  can also be ensured. 
     The fastener S described above can include, but is not limited to a bolt, latch, nail, clip, pin, buckle, screw, washer, and staple. In some embodiments, the fastener is a bolt. 
     While the disclosure has been described in connection with certain embodiments, it is to be understood that the disclosure is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the disclosure, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.