Patent Publication Number: US-10790487-B2

Title: Battery pack having bottom with drainage

Description:
TECHNICAL FIELD 
     The present disclosure relates to a battery pack. 
     The present application claims priority to Korean Patent Application No. 10-2016-0143387 filed on Oct. 31, 2016 in the Republic of Korea, the disclosures of which are incorporated herein by reference. 
     BACKGROUND ART 
     A secondary battery, which is easily applied to various product groups and has electrical characteristics such as high energy density, is universally applied not only for a portable device but also for an electric vehicle (EV), a hybrid electric vehicles (HEV) or the like, which is driven by an electric driving source. The secondary battery is attracting attention as a new environment-friendly energy source for improving energy efficiency since it gives a primary advantage of reducing the use of fossil fuels and also does not generate by-products by the use of energy at all. 
     Secondary batteries widely used at the preset include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries and the like. An operating voltage of the unit secondary battery cell, namely a unit battery cell, is about 2.5V to 4.2V. Therefore, if a higher output voltage is required, a plurality of battery cells may be connected in series to configure a battery pack. In addition, depending on the charge/discharge capacity required for the battery pack, a plurality of battery cells may be connected in parallel to configure a battery pack. Thus, the number of battery cells included in the battery pack may be variously set according to the required output voltage or the demanded charge/discharge capacity. 
     Meanwhile, when a plurality of battery cells are connected in series or in parallel to configure a battery pack, it is common to configure a battery module composed of at least one battery cell first, and then configure a battery pack by using at least one battery module and adding other components. Here, depending on various voltage and capacity requirements, the battery pack including at least one battery module may be used for a home, or battery racks including at least one battery pack may be combined to configure a power storage device for industrial use. 
     In the conventional battery pack, a waterproof and dustproof structure capable of preventing foreign matter such as moisture and dust from penetrating from the outside is particularly important due to characteristics of a battery, which is a secondary battery. In particular, when the battery pack is used as a home energy storage device, the waterproof and dustproof structure may become more important for the safety of a user or the like. 
     Therefore, there is a need to search for a method of providing a battery pack having a waterproof and dustproof structure with better airtightness and efficiency. 
     DISCLOSURE 
     Technical Problem 
     The present disclosure is directed to providing a battery pack having a waterproof and dustproof structure with better airtightness and efficiency. 
     Technical Solution 
     In one aspect of the present disclosure, there is provided a battery pack, which includes at least one battery module and a pack case for packaging the at least one battery module, the battery pack comprising: a case base configured to support the at least one battery module; a case body coupled to the case base to accommodate the at least one battery module; and a case cover coupled to the case body to cover the case body, wherein the case base and the case body are sealed to each other and the case body and the case cover are sealed to each other, respectively, by means of a sealant member along a rim thereof. 
     The case body may include: a first inner case configured to fix the at least one battery module; an outer case configured to surround the first inner case and form an accommodation space for accommodating the at least one battery module; and a second inner case mounted to an upper side of the outer case and coupled to the case cover. 
     The second inner case may be mutually sealed to the outer case by means of the sealant member. 
     The second inner case may be mutually sealed to the case cover by means of the sealant member. 
     The outer case may be mutually sealed to the case base by means of the sealant member. 
     The case base may include a base mount mounted to the at least one battery module; and drainage holes provided at both sides of the base mount and formed to have a step from the base mount. 
     An upper surface of the base mount may be inclined downwards toward the drainage hole. 
     The battery pack may further comprise at least one mesh unit mounted to the drainage hole. 
     The at least one mesh unit may include: a first mesh frame mounted to an upper side of the drainage hole; a first mesh net mounted to the first mesh frame; a second mesh frame mounted to a lower side of the drainage hole; and a second mesh net mounted to the second mesh frame and disposed opposite to the first mesh net. 
     The first mesh net and the second mesh net may be arranged with mutually alternating net structures. 
     The first mesh net and the second mesh net may be spaced apart from each other by at least 2 mm. 
     The at least one mesh unit may include a dust-protecting filter provided between the first mesh net and the second mesh net. 
     The dust-protecting filter may have a volume corresponding to the space between the first mesh net and the second mesh net. 
     The dust-protecting filter may filter off foreign matter including dust with a size of 10 μm or above. 
     The battery pack may be a home energy storage device. 
     Advantageous Effects 
     According to various embodiments as above, it is possible to provide a battery pack having a waterproof and dustproof structure with better airtightness and efficiency. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The accompanying drawings illustrate a preferred embodiment of the present disclosure and together with the foregoing disclosure, serve to provide further understanding of the technical features of the present disclosure, and thus, the present disclosure is not construed as being limited to the drawing. 
         FIG. 1  is a diagram for illustrating a battery pack according to an embodiment of the present disclosure. 
         FIG. 2  is an exploded perspective view showing the battery pack of  FIG. 1 . 
         FIG. 3  is a perspective view showing a case base of a pack case, employed at the battery pack of  FIG. 2 . 
         FIG. 4  is a diagram for illustrating a mesh unit mounted to the case base of  FIG. 3 . 
         FIG. 5  is a cross-sectional view showing the case base of  FIG. 3 . 
         FIG. 6  is a sectional view showing a lower portion of the battery pack of  FIG. 1 . 
         FIG. 7  is a front view showing the battery pack of  FIG. 1 . 
         FIG. 8  is a side view showing the battery pack of  FIG. 1 . 
         FIGS. 9 and 10  are diagrams for illustrating how to transport the battery pack of  FIG. 1 . 
         FIGS. 11 to 13  are diagrams for illustrating how to mount a mount bracket of the battery pack of  FIG. 1 . 
     
    
    
     BEST MODE 
     The present disclosure will become more apparent by describing in detail the embodiments of the present disclosure with reference to the accompanying drawings. It should be understood that the embodiments disclosed herein are illustrative only for better understanding of the present disclosure, and that the present disclosure may be modified in various ways. In addition, for ease understanding of the present disclosure, the accompanying drawings are not drawn to real scale, but the dimensions of some components may be exaggerated. 
       FIG. 1  is a diagram for illustrating a battery pack according to an embodiment of the present disclosure,  FIG. 2  is an exploded perspective view showing the battery pack of  FIG. 1 ,  FIG. 3  is a perspective view showing a case base of a pack case, employed at the battery pack of  FIG. 2 ,  FIG. 4  is a diagram for illustrating a mesh unit mounted to the case base of  FIG. 3 ,  FIG. 5  is a cross-sectional view showing the case base of  FIG. 3 ,  FIG. 6  is a sectional view showing a lower portion of the battery pack of  FIG. 1 ,  FIG. 7  is a front view showing the battery pack of  FIG. 1 , and  FIG. 8  is a side view showing the battery pack of  FIG. 1 . 
     Referring to  FIGS. 1 to 8 , a battery pack  10  is an energy source and may be used as an industrial or home energy storage device. Also, the battery pack  10  may be used as an energy source for a vehicle such as an electric vehicle or a hybrid electric vehicle, which have recently been attracting attention. Hereinafter, this embodiment will be described based on the case where the battery pack  10  is used as a home energy storage device. 
     The battery pack  10  may include a battery module  100 , a pack case  200 , a BMS unit  300 , a memory slot unit  400 , a slot cover  500 , a mesh unit  600  and a handle  700 . 
     At least one battery module  100 , or a plurality of battery modules  100 , may be provided. The following description is based on the case where the battery module  100  is provided in plural. The plurality of battery modules  100  may be stacked along a vertical direction of the battery pack  10  so as to be electrically connected to each other. 
     Each of the plurality of battery modules  100  may include at least one battery cell. The at least one battery cell may be a secondary battery, for example a pouch-type secondary battery. 
     The pack case  200  may package the at least one battery module  100 , or the plurality of battery modules  100  in this embodiment. The pack case  200  may include a case base  210 , a case body  230  and a case cover  250 . 
     The case base  210  forms a bottom of the pack case  200  and may support the plurality of battery modules  100 . The case base  210  may include a base mount  212  and a drainage hole  216 . 
     The base mount  212  forms an appearance of the case base  210  and may support the plurality of battery modules  100 . For this, a battery module  100  disposed on the lowermost side among the plurality of battery modules  100  may be mounted to the base mount  212 . 
     The base mount  212  may have an upper surface that is inclined downward as being closer to the drainage hole  216 , explained later. In other words, the upper surface of the base mount  212  may be inclined downward from the center to both ends. Accordingly, even if water or foreign substances penetrate into the upper surface of the base mount  212 , the penetrating water or foreign substances may easily flow down to the drainage hole  216 , explained later. 
     In addition, a channel elongating toward the drainage hole  216 , explained later, may be provided at the base mount  212 . The channel may be provided at an upper surface of the base mount  212  to guide smooth movement of gas such as smoke toward the drainage hole  216 , explained later. 
     The channel may be provided in a zigzag form at the upper surface of the base mount  212  to ensure a longer channel path. If the channel path is ensured, when a flame occurs within the battery module  10 , it is possible to effectively prevent or delay the movement of the flame toward the drainage hole  216 , explained later, while guiding the movement of the gas along the channel. Accordingly, even though a flame occurs in the battery module  10 , it is possible to effectively prevent or delay that the flame is exposed out of the battery module  10  through the channel. 
     Here, the channel may be prepared by forming a plurality of barrier structures at the upper surface of the base mount  212  or may have a groove structure formed at the upper surface of the base mount  212 . The channel may have other structure as long as it is able to restrict the movement of the flame while guiding the gas to move toward the drainage hole  216 , explained later, from the base mount  212 . 
     The drainage hole  216  communicates with the outside of the pack case  200  and may be provided at both sides of the base mount  212 . When water penetrates into the pack case  200 , the drainage hole  216  may discharge the penetrating water out of the pack case  200 . 
     The drainage hole  216  may be provided below the upper surface of the base mount  212  to form a step with the base mount  212  as much as a predetermined height h. If water penetrates at the upper side of the pack case  200 , the water penetrating at the upper side of the pack case  200  may flow down below the pack case  200  along an inner wall of the pack case  200  and then be discharged out of the pack case  200  through the drainage hole  216 . Here, since the drainage hole  216  is provided below the upper surface of the base mount  212 , it is possible to prevent the water flowing on the upper inner wall of the pack case  200  from penetrating into the upper surface of the base mount  212 . 
     The case body  230  forms the most appearance of the pack case  200  and may be coupled to the case base  210  to accommodate the at least one battery module  100 , or the plurality of battery modules  100  in this embodiment. 
     The case body  230  may include a first inner case  232 , an outer case  234  and a second inner case  236 . 
     The first inner case  232  is to fix the at least one battery module  100 , or the plurality of battery modules  100  in this embodiment, and may include four fixing support bars capable of fixing the plurality of battery modules  100  at four corners of the plurality of battery modules  100  stacked in the vertical direction of the battery pack  10 . 
     The outer case  234  surrounds the first inner case  232  and may form an accommodation space for accommodating the at least one battery module  100 , or the plurality of battery modules  100  in this embodiment. 
     The outer case  234  may have a substantially hexahedral shape to be opened in the vertical direction of the battery pack  10 . The outer case  234  may be integrally formed by extrusion molding. In other words, the outer case  234  may be formed as a single member to cover all of a front portion, a rear portion and both side portions of the plurality of battery modules  100 . The outer case  234  may also be formed as a combination of two members, without being limited to the above. 
     The outer case  234  may be mounted to the first inner case  232  by sliding along the vertical direction of the plurality of battery modules  100 . In detail, the outer case  234  may be mounted to the four fixing support bars of the first inner case  232  by sliding. 
     In this embodiment, since the outer case  234  is mounted to the first inner case  232  by sliding as described above, it is possible to omit an additional bolting member for coupling these members or greatly reduce the number of bolting members. 
     After being mounted by sliding, the outer case  234  may be sealed with the case base  210  along an edge thereof by means of a sealant member to ensure airtightness with the case base  210 . Here, the sealant member may be made of any material capable of ensuring airtightness, for example urethane foam. In other words, the case body  230  and the case base  210  may be sealed to each other by means of the sealant member. 
     The outer case  234  may include a heat-dissipating bead  235 . 
     The heat-dissipating bead  235  is provided at an outer surface of the outer case  234  and may be provided in plural along a length direction of the outer case  234 . The plurality of heat-dissipating beads  235  may effectively dissipate the heat inside the pack case  200  out of the pack case  200  when heat is generated in the pack case  200 . 
     The second inner case  236  is mounted above the outer case  234  and may cover the BMS unit  300 , explained later. The second inner case  236  may be coupled to the case cover  250 , explained later. 
     The second inner case  236  may be sealed with the outer case  234  by means of the sealant member to ensure airtightness with the outer case  234 . In addition, the second inner case  236  may be sealed with the case cover  250 , explained later, by means of the sealant member to ensure airtightness with the case cover  250 , explained later. 
     As described above, in this embodiment, the second inner case  236  and the outer case  234  may be sealed to each other, the second inner case  236  and the case cover  250 , explained later, may be sealed to each other, and the outer case  234  and the case base  210  may be sealed to each other, respectively. Accordingly, in this embodiment, sealing by the sealant member is performed on at least three points among the case base  210 , the case body  230  and the case cover  250 , explained later, of the pack case  200 , and thus it is possible to secure more rigid airtightness of the pack case  200 . 
     The case cover  250  forms an upper side of the pack case  200  and may be coupled to the case body  230  to cover the case body  230 . The case cover  250  may form a space groove S when the case body  230  is coupled thereto. The space groove S is a predetermined space which is exposed only at both side portions and a rear portion of the battery pack  10 , and a handle  700 , explained later, may be provided thereto. This will be described later in more detail in relation to the handle  700 . 
     The BMS unit  300  is provided in the pack case  200  and used for controlling the at least one battery module  100 , or the plurality of battery modules  100  in this embodiment. For this, the BMS unit  300  may be electrically connected to the plurality of battery modules  100 . 
     The memory slot unit  400  is electrically connected to the BMS unit  300 , and a memory unit for firmware update of the BMS unit  300  of the battery pack  10  may be inserted therein. Here, the memory unit is a medium used for the firmware update and may be an SD card. 
     The memory slot unit  400  is disposed between the BMS unit  300  and the pack case  200  inside the pack case  200  and may be partially exposed out of the pack case  200  when the memory unit is inserted. 
     The slot cover  500  may expose the memory slot unit  400  out of the case cover  250  when the memory unit is inserted by a user or the like. For this, the slot cover  500  may be detachably mounted on the case cover  250 . In detail, the slot cover  500  is provided to be rotatably in a horizontal direction of the case cover  250  and may be separated from the case cover  250  or fixed to the case cover  250  according to the rotation. 
     The mesh unit  600  is used to further ensure waterproofing or dustproofing of the battery pack  10 , and at least one mesh pack  600  may be provided. Hereinafter, the present embodiment will be described based on the case where the mesh pack  600  is provided in a pair and respectively mounted to the drainage hole  216 , respectively. 
     The mesh unit  600  may include a first mesh frame  610 , a first mesh net  630 , a second mesh frame  650 , a second mesh net  670  and a dust-protecting filter  690 . 
     The first mesh frame  610  may be mounted above the drainage hole  216 . The first mesh frame  610  may fix the first mesh net  630 , explained later, at an upper side of the drainage hole  216 . 
     The first mesh net  630  is mounted to the first mesh frame  610  and may be disposed above the drainage hole  216 . The first mesh net  630  has a net structure and may prevent foreign substances from penetrating into the pack case  200  from the outside of the pack case  200 . 
     The second mesh frame  650  may be mounted below the drainage hole  216 . The second mesh frame  650  may fix the second mesh net  670 , explained later, at a lower side of the drainage hole  216 . 
     The second mesh net  670  is mounted to the second mesh frame  650  and may be disposed below the underside of the drainage hole  216  to face the first mesh net  630 . 
     The second mesh net  670  has a net structure, similar to the first mesh net  630 , and may prevent foreign substances from penetrating into the pack case  200  from the outside of the pack case  200 . As described above, in this embodiment, the mesh unit  600  may more reliably prevent foreign substances or the like from penetrating into the pack case  200  by means of a double net structure of the first mesh net  630  and the second mesh net  670 . 
     The second mesh net  670  and the first mesh net  630  may be arranged with mutually alternating net structures for more reliable waterproofing or dustproofing. In other words, the net shape of the first mesh net  630  may be interlaced with the net shape of the second mesh net  670  in the vertical direction of the battery pack  10 . 
     In addition, it is also possible that a plurality of mesh nets are provided, more than one pair. If the plurality of mesh nets are provided, namely if three or more mesh nets are provided, the plurality of mesh nets may be stacked in order from top to bottom. Here, the mesh nets facing each other in the vertical direction may be arranged such that the net shapes are mutually alternating in the vertical direction, similar to the first and second mesh nets  630 ,  670 . 
     The first and second mesh nets  630 ,  670  will be described in detail again. 
     Detailed specifications of the first mesh net  630  and the second mesh net  670  are shown in Table 1 below. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                 spacing be- 
                   
               
               
                 kind of 
                 wire 
                 unit net pore 
                   
                 tween first 
               
               
                 mesh net 
                 diameter of 
                 diameter of 
                 poros- 
                 and second 
               
               
                 (Plain 
                 mesh net 
                 mesh net 
                 ity 
                 mesh nets 
                 flame 
               
               
                 Weave) 
                 (mm) 
                 (mm) 
                 (%) 
                 (mm) 
                 passing 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 20 
                 0.457 
                 0.81 
                 41 
                 1 
                 O 
               
               
                   
                   
                   
                   
                 2 or above 
                 X 
               
               
                 30 
                 0.355 
                 0.49 
                 33.5 
                 1 
                 O 
               
               
                   
                   
                   
                   
                 2 or above 
                 X 
               
               
                   
               
            
           
         
       
     
     As shown in Table 1, the mesh nets (the first mesh net  630  and the second mesh net  670 ) may be made of Plain Weave  20  or  30 . 
     First, if the mesh nets (the first mesh net  630  and the second mesh net  670 ) are made of Plain Weave  20 , wires of the net structure may have a diameter of 0.457 mm and a unit net pore of the net structure may have a diameter of 0.81 mm. Also, the overall net structure may have porosity of 41%. 
     And, if the mesh nets (the first mesh net  630  and the second mesh net  670 ) are made of Plain Weave  30 , wires of the net structure may have a diameter of 0.355 mm, and a unit net pore of the net structure may have a diameter of 0.49 mm. Also, the overall net structure may have porosity of 33.5%. 
     In both cases of Plain Weave  20  and the Plain Weave  30 , if a spacing between the first mesh net  630  and the second mesh net  670  is 2 mm or above, the flame may not pass out of the pack case  200 . If fire occurs inside the pack case  200  of the battery pack  10  due to a short circuit or the like, flame and smoke may be generated inside the pack case  200 . At this time, if the flame passes through the mesh unit  600  directly out of the pack case  200  in addition to the smoke, the fire may be rapidly spread due to the flame passing out of the pack case  200 . Thus, the first mesh net  630  and the second mesh net  670  may disposed to be spaced apart from each other by at least 2 mm in order to so as to prevent the flame from passing. 
     The dust-protecting filter  690  is used to filter the foreign substances or the like and may be provided between the first mesh net  630  and the second mesh net  670 . The dust-protecting filter  690  may employ a filter capable of filtering foreign substances such as dust of at least 10 μm. 
     The dust-protecting filter  690  may have a volume corresponding to the space between the first mesh net  630  and the second mesh net  670 . In other words, the dust-protecting filter  690  may be sized to completely fill the space between the first mesh net  630  and the second mesh net  670 . This is to more reliably prevent the foreign substances such as dust from passing through the space between the first mesh net  630  and the second mesh net  670 . 
     The handle  700  is used to guide the delivery of the battery pack  10  by the user during the transportation of the battery pack  10  and may be provided at both side surfaces of the case cover  250 . 
     The handle  700  may form a space groove S when the case body  230  and the case cover  250  are coupled. Seeing the structure of the handle  700  in more detail, one end of the handle  700  may be spaced a predetermined distance from the front surface of the case cover  250  to the rear of the case cover  250 , and the other end of the handle  700  may be disposed at the rear surface of the case cover  250 . 
     The handle  700  may be formed integrally with the case cover  250 . Accordingly, in this embodiment, the handle  700  is integrally formed at the case cover  250 , instead of being separately attached to the pack case  200 , and thus it is possible to reduce cost and time for manufacturing the handle. 
     Hereinafter, the transportation of the battery pack  10  by using the handle  700  will be described in more detail. 
       FIGS. 9 and 10  are diagrams for illustrating how to transport the battery pack of  FIG. 1 . 
     Referring to  FIGS. 9 and 10 , first, the handle  700  of the battery pack  10  is disposed in the space groove S and exposed only at both side portions and a rear portion of the battery pack  10 , so that the handle  700  may not be exposed to the user at the front portion of the battery pack  700 . In other words, the front portion of the battery pack  10  does not protrude, and thus the beauty of the battery pack  10  may not be deteriorated in an aesthetic point of view. 
     When the user or the like wants to move the battery pack  10 , the user may put the hands into the space grooves S provided at both sides of the pack case  200 , grab the handle  700  and then move the battery pack  10 . Since the user or the like may transport the battery pack  10  by holding the handles  700  provided at both sides of the pack case  700 , the battery pack  10  may be transported more reliably. 
       FIGS. 11 to 13  are diagrams for illustrating how to mount a mount bracket of the battery pack of  FIG. 1 . 
     Referring to  FIGS. 11 to 13 , the battery pack  10  may further include a mount bracket  800 . 
     The mount bracket  800  is detachably mounted to the pack case  200  and may allow the battery pack  10  to be mounted to an exterior structure W. The exterior structure W may be, for example, a wall of a house. In other words, the mount bracket  800  may guide the battery pack  10  to be fixed in a wall-hanging manner. 
     The mount bracket  800  may include a pack mounting portion  810  and a structure mounting portion  830 . 
     The pack mounting portion  810  is mounted to the pack case  200  by using a screw member or the like and may be disposed within the space groove S. The structure mounting portion  830  is bent from the pack mounting portion  810  and may be mounted to the exterior structure W by using the screw member or the like. 
     Meanwhile, the pack mounting portion  810  and the structure mounting portion  830  may be disposed within the space groove S. In other words, the mount bracket  800  may be disposed within the space groove S when mounted to the pack case  200 . Accordingly, when being mounted to the pack case  10  and the exterior structure W, the mount bracket  800  may be hidden by the front surface of the case cover  250  in front of the battery pack  10 . Thus, when the battery pack  10  is mounted in a wall-hanging manner, the mount bracket  800  is not observed in front of the battery pack  10  and thus may not hinder the aesthetic sense in terms of design. 
     As described above, the battery pack  10  of this embodiment may have a more airtight and efficient waterproofing and dustproofing structure by means of the above-mentioned structure. In addition, the battery pack  10  of this embodiment may be easily transported and installed by means of the above-mentioned structure and may secure an aesthetic sense in terms of design. 
     While the embodiments of the present disclosure have been shown and described, it should be understood that the present disclosure is not limited to the specific embodiments described, and that various changes and modifications can be made within the scope of the present disclosure by those skilled in the art, and these modifications should not be understood individually from the technical ideas and views of the present disclosure.