Patent Publication Number: US-2022231376-A1

Title: Battery pack and device including the same

Description:
CROSS CITATION WITH RELATED APPLICATION(S) 
     This application claims the benefit of Korean Patent Application No. 10-2019-0158412 filed on Dec. 2, 2019 with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a battery pack and a device including the same, and more particularly, to a battery pack containing a gasket and a device including the same. 
     BACKGROUND ART 
     Recently, along with the increase of the technological development and demand for a mobile device, demand for a secondary battery capable of charging and discharging as an energy source rapidly increases, and accordingly, many researches of the battery capable of meeting a variety of needs are performed. 
     Further, the secondary battery has attracted considerable attention as a power source for electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (Plug-in HEV), which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuels. 
     Therefore, an electric vehicle (EV), which can be driven only by a secondary battery, and a hybrid electric vehicle (HEV), which combines a conventional engine with a secondary battery, have been developed and some thereof have been commercialized. A nickel-metal hydride (Ni-MH) secondary battery has been mainly used as the power source of EV, HEV and the like. Recently, however, studies using lithium secondary batteries having high energy density, high discharge voltage and output stability have been actively conducted. 
     When such a secondary battery is used as an automobile power source, the secondary battery is used in the form of a battery pack containing a plurality of battery modules or a battery module assembly. Vehicle battery packs are configured such that rubber gaskets are located in upper and lower cases in order to seal the battery pack. 
       FIG. 1  is a view showing the appearance of a conventional battery pack.  FIG. 2  is an enlarged view of part A of  FIG. 1 .  FIG. 3  is a view showing a gas discharge direction of a conventional battery pack. 
     Referring to  FIGS. 1 to 3 , the conventional battery pack is formed of an upper case  11  and a lower case  12 , a rubber gasket  20  fixed via a fastening portion  30  is formed between the upper case  11  and the lower case  12 , and the inside of the battery pack was sealed via the gasket  20 . The gasket  20  is uniformly formed of a rubber material along the circumference between the cases, but when the gasket of the same material is uniformly formed around the case in this way, the gas through ignition may be discharged from all the gasket circumferential directions during the occurrence of an ignition phenomenon inside the battery pack as shown in  FIG. 3 . 
     This is because, when a pressure exceeding the sealing force is applied to the gasket  20 , discharge can occur in all circumferential directions through the gasket  20  surface uniformly formed in the circumferential direction. However, since the vehicle battery pack is installed inside the vehicle, there is a problem that the vehicle and passengers may be in danger if the hot gas is discharged in the direction of the vehicle parts including the fuel tank. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     It is an object of the present disclosure to provide a battery pack that can set the direction of gas discharge at the time of ignition, and a device including the same. 
     However, the problem to be solved by embodiments of the present disclosure is not limited to the above-described problems, and can be variously expanded within the scope of the technical idea included in the present disclosure. 
     Technical Solution 
     A battery pack according to one embodiment of the present disclosure includes: a lower case and an upper case; and an annular gasket formed between the lower case and the upper case to seal between the cases, wherein the gasket includes first and second sealing parts connected to each other, and wherein a melting point of the second sealing part is lower than the melting point of the first sealing part. 
     Projection parts may be formed at both ends of the second sealing part, and groove parts may be formed at both ends of the first sealing part, and the projection parts are fitted into the groove parts. 
     The width of the projection part of the second sealing part may be wider than the width of the groove part of the first sealing part. 
     A bush may be formed in the center of the second sealing part, and a fastening member may be inserted into the bush to fix the position of the second sealing part. 
     Gas discharge channels may be formed on both sides of the bush through the melting of the second sealing part, and gas inside the cases may be discharged to the outside through the gas discharge channels. 
     The fastening member may be formed of a bolt and a nut. 
     A fastening part may be formed in the upper case and the lower case, and the fastening member may connect the bush and the fastening part. 
     The first sealing part may be formed of EPDM-based rubber, and the second sealing part may be formed of NR-based rubber. 
     The second sealing part may be formed in plural numbers. 
     The gasket may be formed a square shape, and the plurality of second sealing parts may be arranged at one corner part of the gasket. 
     The gasket may be formed in a square shape, and the plurality of the second sealing parts may be arranged at one edge part of the gasket and other edge parts connected to the one edge port. 
     A device including the battery pack is provided, wherein the second sealing part may be formed in a portion facing the outside among the gasket parts. 
     Advantageous Effects 
     According to the embodiments of the present disclosure, it is possible to discharge the gas inside the battery pack through the gas discharge channel formed by melting the second sealing part formed in the direction in which vehicle parts are not installed, thereby improving the stability of the battery pack installed in the device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing the appearance of a conventional battery pack. 
         FIG. 2  is an enlarged view of part A in  FIG. 1 . 
         FIG. 3  is a diagram showing the gas discharge direction of the conventional battery pack. 
         FIG. 4  is an exploded perspective view showing a battery pack according to one embodiment of the present disclosure. 
         FIG. 5  is a diagram showing a gasket according to one embodiment of the present disclosure. 
         FIG. 6  is a diagram showing a second sealing part formed in the part B of  FIG. 5 . 
         FIG. 7  is a diagram showing a state in which the second sealing part of  FIG. 6  is disassembled. 
         FIG. 8  is a diagram showing a state in which a gas discharge channel according to one embodiment of the present disclosure is formed. 
         FIG. 9  is a view of the gas discharge channel according to one embodiment of the present disclosure as viewed from a different angle from that of  FIG. 8 . 
         FIG. 10  is a diagram showing a gas discharge position of the gasket according to one embodiment of the present disclosure. 
         FIG. 11  is a diagram showing a gas discharge position of the battery pack according to one embodiment of the present disclosure. 
         FIG. 12  is a diagram showing a second sealing part according to another embodiment of the present disclosure. 
         FIG. 13  is a diagram showing a second sealing part according to yet another embodiment of the present disclosure. 
         FIG. 14  is a diagram showing a state in which the battery pack according to one embodiment of the present disclosure is mounted on the device D. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. The present disclosure may be modified in various different ways, and is not limited to the embodiments set forth herein. 
     Portions that are irrelevant to the description will be omitted to clearly describe the present disclosure, and like reference numerals designate like elements throughout the specification. 
     Further, in the figures, the size and thickness of each element are arbitrarily illustrated for convenience of description, and the present disclosure is not necessarily limited to those illustrated in the figures. In the figures, the thickness of layers, regions, etc. are exaggerated for clarity. In the figures, for convenience of description, the thicknesses of some layers and regions are shown to be exaggerated. 
     Further, throughout the specification, when a portion is referred to as “including” a certain component, it means that it can further include other components, without excluding the other components, unless otherwise stated. 
     Hereinafter, a battery pack according to one embodiment of the present disclosure will be described. 
       FIG. 4  is an exploded perspective view showing a battery pack according to one embodiment of the present disclosure.  FIG. 5  is a diagram showing a gasket according to one embodiment of the present disclosure. 
     Referring to  FIGS. 4 and 5 , in the battery pack according to one embodiment of the present disclosure, a lower case  120  and an upper case  110  are combined with a cell assembly held in a built-in state. Inside the battery pack, cell assemblies having different numbers form an upper and lower stacked structure. 
     The gasket  200  is formed in an annular shape along the outer peripheries of the cases between the lower case  120  and the upper case  110  to seal between the cases. The gasket  200  may be formed of a rubber material. 
     The gasket  200  may be connected to the cases through a fastening part  111  formed on the upper case  110  and a fastening portion  121  formed on the lower case  120 . The fastening part  111  formed in the upper case  110  may be formed in plural numbers along the circumference where the upper case  110  meets the lower case  120 . Similarly, a plurality of fastening parts  121  formed on the lower case  120  may also be formed along the circumference where the lower case  120  meets the upper case  110 . The gasket  200  may also be formed with a plurality of fastening parts along the annular circumference. The fastening part of each upper case  110 , the fastening part of the lower case  120 , and the fastening part of the gasket  200  are all formed at positions corresponding to the vertical direction, and the respective fastening parts may be vertically connected to each other via a fastening member. The fastening member may be formed of a bolt and a nut. 
     Conventionally, all portions of the gasket were formed of the same material, and the gasket was sealed around the upper and lower cases with the same sealing force. However, if pressure exceeding the sealing force of the gasket is generated due to internal ignition, gas may be discharged through all gasket surfaces in the 360-degree direction. When the battery pack is mounted on the vehicle, there was a risk of hot gases being discharged in the direction of the fuel tank and vehicle parts. 
     However, according to one embodiment of the present disclosure, as shown in  FIG. 5 , the gasket  200  includes a first sealing part  210  and a second sealing part  220  connected to each other. When the temperature rises, the second sealing part  220  is melted before the first sealing part  210 , and gas inside the cases is discharged to the outside through the melted second sealing part  220 . 
     The first sealing part  210  according to the present disclosure may be formed of EPDM-based rubber, and the second sealing part  220  may be formed of NR-based rubber. The maximum application temperature of EPDM-based rubber is 150 degrees, and the maximum application temperature of NR-based rubber is 90 degrees. NR-based rubber has a lower melting point than EPDM-based rubber, so it may melt first when the temperature rises. Therefore, the second sealing part  220  is melted before the first sealing part  210 , and gas inside the battery pack may be discharged to the outside through the melted second sealing part. 
     Therefore, the second sealing part  220  according to the embodiment of the present disclosure can be provided at a location desired by the user, and gas inside the battery pack may be discharged in the direction in which the provided second sealing part  220  is located, whereby the position of the second sealing part  220  can be set in the direction in which vehicle parts and fuel tanks are not located, to thereby prevent in advance a risk that may occur through the discharged gas. 
     Hereinafter, a second sealing part according to one embodiment of the present disclosure will be described in more detail. 
       FIG. 6  is a diagram showing a second sealing part formed in the part B of  FIG. 5 .  FIG. 7  is a diagram showing a state in which the second sealing part of  FIG. 6  is disassembled.  FIG. 8  is a diagram showing a state in which a gas discharge channel according to one embodiment of the present disclosure is formed. 
     Referring to  FIGS. 6 to 8 , the second sealing part  220  according to one embodiment of the present disclosure may include protrusion parts  221  and  222  formed at both ends, and a bush  223  formed at the center. 
     The protrusion parts  221  and  222  may be formed so as to project toward different directions from the center of both ends of the second sealing part  220 . The protrusion parts  221  and  222  can be respectively fitted with groove parts  211  and  212  formed at both ends of the first sealing part  210 . 
     According to one embodiment of the present disclosure, as shown in  FIG. 7 , the width W 2  of the protrusion parts  221  and  222  of the second sealing part  220  may be formed wider than the width W 1  of the groove parts  211  and  212  of the first sealing part  210 . In this way, the width W 2  of the protrusion parts  221  and  222  is formed wider than the width W 1  of the groove parts  211  and  212 , and thus the first sealing part  210  and the second sealing part  220  can be firmly connected to each other through an insertion fitting based on an overlapping structure. 
     The bush  223  is formed in the center of the third sealing part  220 , and is formed to correspond in a vertical direction to any one of the fastening parts  111  of the upper case  110  and any one of the fastening parts  121  of the lower case  120 , so that the second sealing part  220  may be connected to the upper case  110  and the lower case  120  via the fastening member  300  to fix the position of the second sealing part  220 . More specifically, the second sealing part  220  is disposed at a location desired by the user among the circumferential portions to which the upper and lower cases  110  and  120  are connected, and the second sealing part  220  disposed at a desired position via the bush  223  may be fixed between the upper and lower cases  110  and  120 . 
     The fastening member  300  may be connected via the fastening parts  111  and  121  of the bush  223  and the upper and lower cases  110  and  120  formed at positions corresponding thereto. According to one embodiment of the present disclosure, the fastening member  300  may be formed of a bolt and a nut, but is not limited thereto, and a fastening member may be mounted through various embodiments. 
     Hereinafter, the gas discharge direction according to an embodiment of the present disclosure will be described. 
       FIG. 8  is a diagram showing a state in which a gas discharge channel according to one embodiment of the present disclosure is formed.  FIG. 9  is a view of the gas discharge channel according to one embodiment of the present disclosure as viewed from a different angle from that of  FIG. 8 .  FIG. 10  is a diagram showing a gas discharge position of the gasket according to one embodiment of the present disclosure.  FIG. 11  is a diagram showing a gas discharge position of the battery pack according to one embodiment of the present disclosure. 
     Referring to  FIGS. 8 to 11 , the gas discharge channels  224  and  225  according to one embodiment of the present disclosure may be formed on both sides of the bush  223  of the second sealing part  220 . As the temperature of the battery pack rises due to the ignition phenomenon inside the battery pack, the second sealing part  220  with a low melting point melts before the first sealing part  210 . As the second sealing part  220  is melted, gas discharge channels  224  and  225  may be formed on both sides of the bush  223 . Gas inside the battery pack may be discharged to the outside through the gas discharge channels  224  and  225 . 
     Hereinafter, a plurality of second sealing parts formed according to other embodiments of the present disclosure will be described. 
       FIG. 12  is a diagram showing a second sealing part according to another embodiment of the present disclosure.  FIG. 13  is a diagram showing a second sealing part according to yet another embodiment of the present disclosure. 
     Referring to  FIG. 12 , the second sealing part  220  according to another embodiment of the present disclosure may be formed in plural numbers, and the plurality of second sealing parts  220  may be disposed at one corner of the gasket  200  formed in a square shape. Referring to  FIG. 13 , the second sealing part  220  according to another embodiment of the present disclosure may be formed in plural numbers, and the plurality of second sealing parts  220  may be disposed at one corner portion of the gasket  200  formed in a square shape and other corner portions connected to the one corner portion, respectively. 
     Hereinafter, a state in which the battery pack according to one embodiment of the present invention is mounted on the device D will be described. 
       FIG. 14  is a diagram showing a state in which the battery pack according to one embodiment of the present disclosure is mounted on the device D. 
     Referring to  FIGS. 10 and 14 , the second sealing part  220  of the battery pack according to another embodiment of the present disclosure may be formed in the portion of the gasket  200  that faces the outside. Therefore, the hot gas is not discharged in the direction of the parts formed inside the device, but the gas is discharged to the outside, thereby protecting the parts installed in the device. According to one embodiment of the present disclosure, the device may be formed for a vehicle, and the battery pack is disposed at the backward part of the vehicle. The second sealing part  220  is also disposed toward the backward part of the vehicle so as to face the outside, so that hot gas is discharged to the external space to protect parts installed in the vehicle. 
     In addition, the device according to another embodiment of the present invention includes the above-mentioned battery pack as a power source. These devices may be applied to transportation means such as an electric bicycle, an electric vehicle, a hybrid vehicle, but the present disclosure is not limited thereto and can be applied to various devices that can use the secondary battery. 
     Although the preferred embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present disclosure defined in the following claims also belong to the scope of rights. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               100 : case 
               110 : upper case 
               111 : fastening part 
               120 : lower case 
               121 : fastening part 
               200 : gasket 
               210 : first sealing part 
               211 ,  212 : groove part 
               220 : second sealing part 
               221 ,  222 : projection part 
               223 : bush 
               224 ,  225 : gas discharge channel 
               300 : fastening member