Patent Publication Number: US-2022234432-A1

Title: Power storage device

Description:
This non-provisional application is based on Japanese Patent Application No. 2021-011926 filed on Jan. 28, 2021 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     Field 
     The present disclosure relates to a power storage device mounted on a vehicle. 
     Description of the Background Art 
     Japanese Patent Laying-Open No. 2014-193692 discloses a conventional power storage device in which a junction box is disposed at a positon behind a housing case that houses a power storage module. The housing case is disposed below the floor panel, and the junction box is disposed above the floor panel at a positon behind the housing case. The junction box is disposed on a cross member that extends between a pair of rear wheel houses. A rear side member protrudes rearward from the cross member. 
     In the power storage device disclosed in Japanese Patent Laying-Open No. 2014-193692, when the vehicle encounters a rear end collision, the floor panel and the rear side member undergo a bending deformation by rotating upward about a rear portion of the cross member. Thereby, it is possible to reduce an impact force applied to the junction box disposed on the cross member. 
     SUMMARY 
     Unlike the power storage device disclosed in Japanese Patent Laying-Open No. 2014-193692, depending on the structure of a vehicle, the installation area of a junction box and the installation area of a housing case may not be partitioned by the floor panel. In this case, in order to protect the junction box, the junction box is generally disposed in a robust housing case. 
     However, if the junction box is disposed adjacent to the power storage module in the housing case, the length of the housing case becomes longer. In this case, as compared with the case where the junction box is disposed adjacent to the housing case, the length of the entire power storage device becomes greater. If the length of the housing case becomes greater, in order to ensure sufficient buckling strength or the like, the cross section of the housing case becomes greater by the power of ⅔ or the power of 2 in accordance with the length. 
     Further, when a reinforcing member is disposed at a central position of the housing case so as to reinforce the housing case, in order to prevent the power storage module from interfering with the reinforcing member, the power storage module is divided into a plurality of components and disposed in the housing case, which makes the total size of the components and the housing case greater. 
     The present disclosure has been made in view of the aforementioned problems, and an object of the present disclosure is to provide a power storage device having a reduced size while preventing an impact force from being transmitted to a power storage module and an electronic device. 
     The power storage device according to an embodiment of the present disclosure includes a power storage module, a first housing that houses therein the power storage module, an electronic device, a second housing that is arranged side by side with the first housing and houses therein the electronic device, and a protection unit that protects the second housing. The protection unit is disposed to overlap with the second housing in a second direction orthogonal to a first direction in which the first housing and the second housing are arranged side by side. The protection unit includes a load receiving member that receives a load applied from the first direction, a pair of load transmitting members connected between the load receiving member and the first housing so as to transmit the load applied to the load receiving member to the first housing, and a reinforcing member that reinforces the pair of load transmitting members. The pair of load transmitting members is disposed to face each other in a third direction orthogonal to the first direction and the second direction in such a manner that a distance between the pair of load transmitting members increases from the load receiving member toward the first housing. 
     According to the configuration mentioned above, the first housing and the second housing are arranged side by side. Therefore, as compared with the case where the second housing and the power storage module are arranged side by side inside the first housing, it is possible to reduce the physical size of the power storage device. In addition, since the protection unit is disposed to overlap with the second housing in the second direction, it is possible to reduce the installation space of the protection unit and the physical size of the power storage device. 
     Further, when an impact force is applied from the first direction in which the first housing and the second housing are arranged side by side, the impact force is applied to the impact force receiving member of the protection unit. The impact force applied to the impact force receiving member is transmitted to the first housing by the pair of impact force transmitting members. In the present disclosure, the pair of impact force transmitting members is reinforced by the reinforcing member. Thus, the pair of impact force transmitting members is prevented from being damaged by the impact force. Therefore, it is possible for the pair of impact force transmitting members to transmit the impact force to the first housing while preventing the impact force from being transmitted to the second housing. Accordingly, it is possible to prevent the impact force from being transmitted to the electronic device housed in the second housing. 
     In addition, since the pair of impact force transmitting members is disposed in such a manner that the distance between the pair of impact force transmitting members increases toward the first housing, the impact force is transmitted to both end portions of the first housing instead of the central portion thereof in the third direction. Since the impact force is transmitted to both end portions of the first housing having higher rigidity, the first housing is prevented from being deformed, which makes it possible to prevent the impact force from being transmitted to the power storage module. 
     In the power storage device according to the present disclosure, it is preferable that when viewed from the second direction, the load receiving member is disposed to protrude from the second housing in the first direction. 
     According to the configuration mentioned above, when an impact force is applied from the first direction, the impact force is more reliably applied to the impact force receiving member. 
     In the power storage device according to the present disclosure, it is preferable that the first housing includes a side surface facing the second housing in the first direction, and each of the pair of load transmitting members is connected to a corresponding one of both end portions of the side surface in the third direction. 
     According to the configuration mentioned above, since both end portions of the side surface are located nearby corners of the first housing, the rigidity of both end portions of the side surface is higher than that of the central portion of the side surface. Since the impact force is transmitted to both end portions of the side surface by the pair of load transmitting members, the first housing is less likely to be damaged. 
     In the power storage device according to the present disclosure, it is preferable that when viewed from the second direction, a connection portion of each of the pair of load transmitting members connected to a corresponding one of both end portions of the side surface is located outside the power storage module. 
     According to the configuration mentioned above, since the impact force is applied to the side surface located outside the power storage module, even if the side surface is deformed, it is possible to prevent the side surface from coming into contact with the power storage module, which makes it possible to prevent the impact force from being transmitted to the power storage module. 
     In the power storage device of the present disclosure, the reinforcing member includes a connection member to connect the pair of load transmitting members. 
     According to the configuration mentioned above, it is possible to prevent the pair of load transmitting members from being deformed in such a manner that the end portions of the pair of load transmitting members nearby the first housing are widened by the impact force transmitted to the pair of load transmitting members. Thus, it is possible to prevent the pair of load transmitting members from being damaged, which makes it possible to prevent the impact force from being transmitted to the second housing. 
     The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view illustrating a power storage device mounted on a vehicle according to an embodiment; 
         FIG. 2  is a plan view illustrating a protection unit and a first housing that houses a power storage module according to the present embodiment; 
         FIG. 3  is a plan view illustrating a protection unit according to a first modification; 
         FIG. 4  is a plan view illustrating a protection unit according to a second modification; and 
         FIG. 5  is a plan view illustrating a protection unit according to a third modification. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the following embodiment, the same or equivalent portions in the drawings will be denoted by the same reference numerals, and the description thereof will not be repeated. 
     (Embodiment) 
       FIG. 1  is a schematic view illustrating a power storage device  100  mounted on a vehicle according to an embodiment. The power storage device  100  according to the present embodiment will be described with reference to  FIG. 1 . 
     The power storage device  100  according to the present embodiment is used in a vehicle such as a hybrid electric vehicle (HEV) provided with an engine and a motor generator as a power source or a battery electric vehicle (BEV) without an engine. 
     As illustrated in  FIG. 1 , the power storage device  100  is disposed above a floor panel  1 , for example. The power storage device  100  may be disposed below the floor panel  1 . 
     The power storage device  100  includes a power storage module  10 , a first housing  20 , an electronic device  30 , a second housing  40 , and a protection unit  50 . 
     The power storage module  10  includes a plurality of power storage cells  11 . The plurality of power storage cells  11  are disposed in a direction parallel to a first direction (DR 1  direction) which will be described later. The plurality of power storage cells  11  are, for example, secondary batteries such as nickel-hydrogen batteries or lithium-ion batteries. The power storage cell  11  has, for example, a rectangular shape. The shape of the power storage cell  11  is not limited to a rectangular shape, and may be a cylindrical shape. The power storage cell  11  may be a power storage cell containing a liquid electrolyte or a power storage cell containing a solid electrolyte. 
     The power storage module  10  is housed in the first housing  20 . The first housing  20  has a substantially rectangular parallelepiped shape. The first housing  20  is arranged side by side with the second housing  40  in the first direction (DR 1  direction). The first direction is parallel to the width direction of the vehicle, for example, when the power storage device  100  is mounted on the vehicle. The first housing  20  is manufactured by, for example, aluminum die casting. 
     The electronic device  30  is, for example, a control ECU that controls the power storage module  10 . The electronic device  30  is housed in the second housing  40 . The electronic device  30  and the second housing  40  constitute a junction box, for example. 
     The second housing  40  has a substantially box shape. The second housing  40  is arranged side by side with the first housing  20 . The second housing  40  is disposed on one side of the first housing  20  in the first direction. The second housing  40  may be disposed adjacent to the first housing  20  or with a gap between the first housing  20 . The second housing  40  may be made of a metal material or a resin member. 
     The protection unit  50  protects the second housing  40 . Specifically, when an impact force is applied from the first direction due to a side collision or the like of the vehicle, the protection unit  50  prevents the impact force from being transmitted to the second housing  40 . 
     The protection unit  50  is disposed to overlap with the second housing  40  in a second direction (DR 2  direction). The second direction is orthogonal to the first direction in which the first housing  20  and the second housing  40  are arranged side by side. The second direction is parallel to the vertical direction (perpendicular direction), for example. 
     The protection unit  50  is disposed below the second housing  40  and arranged side by side with the first housing  20 . An end portion  50   a  of the protection unit  50  in the first direction is disposed to protrude from the second housing  40  in the first direction. 
       FIG. 2  is a plan view illustrating the protection unit and the first housing that houses the power storage module according to the present embodiment. The protection unit  50  will be described in detail with reference to  FIG. 2 . 
     The protection unit  50  includes a load receiving member  51 , a pair of load transmitting members  52 , and a reinforcing member  53 . The load receiving member  51 , the pair of load transmitting members  52  and the reinforcing member  53  are made of, for example, a metal material having impact resistance. The material of the load receiving member  51 , the pair of load transmitting members  52  and the reinforcing member  53  is not limited to a metal material, and the material may be appropriately selected as long as it has a predetermined strength. 
     The load receiving member  51  has a substantially block shape. The load receiving member  51  extends in a third direction (DR 3  direction) orthogonal to the first direction and the second direction. For example, the third direction is parallel to the front-rear direction of the vehicle when the power storage device  100  is mounted on the vehicle. 
     An end portion  51   a  (the end portion  50   a ) of the load receiving member  51  in the first direction is disposed to protrude from the second housing  40  in the first direction. Thus, when an impact force is applied from the first direction, the impact force is more reliably applied to the load receiving member  51 . 
     The pair of load transmitting members  52  transmits the load applied to the load receiving member  51  to the first housing  20 . The pair of load transmitting members  52  is connected between the load receiving member  51  and the first housing  20 . The pair of load transmitting members  52  is disposed to face each other in the third direction. The pair of load transmitting members  52  is disposed in such a manner that a distance between the pair of load transmitting members  52  increases from the load receiving member  51  toward the first housing  20 . 
     The first housing  20  has side surfaces  21 ,  22 ,  23  and  24 . The side surfaces  21  and  24  face each other in the first direction. The side surface  21  faces the second housing  40  in the first direction. The side surfaces  22  and  23  face each other in the third direction. The side surface  22  is connect between an end portion of the side surface  21  and an end portion of the side surface  24  in the third direction. The side surface  23  is connect between the other end portion of the side surface  21  and the other end portion of the side surface  24  in the third direction. 
     As described above, since the side surfaces  22  and  23  are connected to both end portions of the side surface  21  in the third direction, the rigidity of both end portions of the side surface  21  is higher than that of the central portion of the side surface  21 . 
     Each of the pair of load transmitting members  52  is connected to a corresponding one of both end portions of the side surface  21  in the third direction. When viewed from the second direction, a connection portion  52   a  of each of the pair of load transmitting members  52  connected to a corresponding one of both end portions of the side surface  21  is located outside the power storage module  10 . 
     The reinforcing member  53  reinforces the pair of load transmitting members  52 . The reinforcing member  53  includes a first connection member  54  and a second connection member  55 . The first connection member  54  is configured to connect the pair of load transmitting members  52 . The first connection member  54  extends in a direction parallel to the third direction so as to bridge the pair of load transmitting members  52 . 
     The second connection member  55  has a substantially V-shape. Two arms of the V-shape are connected to the pair of load transmitting members  52 , and the bottom of the V-shape is connected to the central portion of the first connection member  54 . 
     When the vehicle encounters a side collision and an impact force is applied from the first direction, the impact force is applied to the load receiving member  51  of the protection unit  50 . The impact force (load) applied to the load receiving member  51  is dispersed and transmitted to the first housing  20  by the pair of load transmitting members  52 . As described above, the pair of load transmitting members  52  is reinforced by the reinforcing member  53 . Thus, the pair of load transmitting members  52  is prevented from being damaged by the impact force. Therefore, it is possible for the pair of load transmitting members  52  to transmit the impact force to the first housing  20  while preventing the impact force from being transmitted to the second housing  40 . Accordingly, it is possible to prevent the impact force from being transmitted to the electronic device  30  housed in the second housing  40 . 
     Further, since the pair of load transmitting members  52  is disposed in such a manner that the distance between the pair of load transmitting members  52  increases toward the first housing  20 , the impact force is transmitted to both end portions of the first housing  20  instead of the central portion thereof in the third direction. Since the rigidity of both end portions of the first housing  20  is higher than that of the central portion thereof, the first housing  20  is prevented from being deformed, which makes it possible to prevent the impact force from being transmitted to the power storage module  10 . 
     In addition, as described above, the first housing  20  and the second housing  40  are arranged side by side. Therefore, as compared with the case where the power storage module  10  and the second housing  40  are arranged side by side inside the first housing  20 , it is possible to reduce the physical size of the power storage device. 
     In other words, if the power storage module  10  and the second housing  40  are arranged side by side inside the first housing  20 , it is necessary to provide a gap between the power storage module  10  and the second housing  40  and a gap between the second housing  40  and the side surface  21 , which increases the length of the first housing  20  in the first direction. 
     Further, in the present embodiment, since the protection unit  50  is disposed to overlap with the second housing  40  in the second direction, it is possible to reduce the installation space of the protection unit  50  and the physical size of the power storage device  100 . 
     As described above, it is possible to prevent the impact force from being transmitted to the power storage module  10  and the electronic device  30  while reducing the physical size of the power storage device  100  according to the present embodiment. 
     Further, according to the power storage device  100  of the present embodiment, as described above, since the rigidity of both end portions of the side surface  21  is higher, and each of the pair of load transmitting members  52  is connected to a corresponding one of both end portions of the side surface  21 , it is possible to prevent the first housing  20  from being deformed. Accordingly, it is possible to prevent the first housing  20  from coming into contact with the power storage module  10 , which makes it possible to further prevent the impact force from being transmitted to the power storage module  10 . 
     In addition, as described above, since the connection portion of each of the pair of load transmitting members  52  connected to a corresponding one of both end portions of the side surface  21  is located outside the power storage module, even when the side surface is deformed, it is possible to prevent the side surface from coming into contact with the power storage module. Thus, it is possible to further prevent the impact force from being transmitted to the power storage module  10 . 
     As illustrated in the following  FIGS. 3 to 5 , the protection unit  50  according to the present embodiment may be modified to a protection unit  50 A according to a first modification, a protection unit  50 B according to a second modification, or a protection unit  50 C according to a third modification. 
     (First Modification) 
       FIG. 3  is a plan view illustrating a protection unit  50 A according to a first modification. The protection unit  50 A according to the first modification will be described with reference to  FIG. 3 . 
     As illustrated in  FIG. 3 , the protection unit  50 A according to the first modification differs from the protection unit  50  according to the present embodiment in the structure of a reinforcing member  53 A. The reinforcing member  53 A includes only a first connection member  54 A. 
     The first connection member  54 A has a substantially V-shape. Two arms of the V-shape are disposed inside the pair of load transmitting members  52 , and are respectively connected to the end portions of the pair of load transmitting members  52  nearby the load receiving member  51 . The bottom of the V-shape is connected to the first housing  20 . More specifically, the bottom of the V-shape is connected to the central portion of the side surface  21  in the third direction. 
     Even with the protection unit  50 A according to the first modification, it is possible to obtain substantially the same effect as that of the present embodiment. In the first modification, the first connection member  54 A also functions to transmit the load to the first housing  20 , and the load is dispersed among the pair of load transmitting members  52  and the first connection member  54 A. 
     (Second Modification) 
       FIG. 4  is a plan view illustrating a protection unit  50 B according to a second modification. The protection unit  50 B according to the second modification will be described with reference to  FIG. 4 . 
     As illustrated in  FIG. 4 , the protection unit  50 B according to the second modification differs from the protection unit  50  according to the present embodiment in the structure of a reinforcing member  53 B. The reinforcing member  53 B includes a first connection member  54 B and a second connection member  55 B. 
     The first connection member  54 B is disposed inside the pair of load transmitting members  52 , and is connected to the end portions of the pair of load transmitting members  52  nearby the first housing  20 . The second connection member  55 B extends in a direction parallel to the third direction. 
     The second connection member  55 B is disposed at a substantially central position between the first connection member  54 B and the load receiving member  51 . The second connection member  55 B is disposed inside the pair of load transmitting members  52 , and is connected to substantially the central portions of the pair of load transmitting members  52  in the extending direction of the load transmitting members  52 . The width of the second connection member  55 B in the first direction may be larger than the width of the first connection member  54 B in the first direction. 
     Even with the protection unit  50 B according to the second modification, it is possible to obtain substantially the same effect as that of the present embodiment. 
     (Third Modification) 
       FIG. 5  is a plan view illustrating a protection unit  50 C according to a third modification. The protection unit  50 C according to the third modification will be described with reference to  FIG. 5 . 
     As illustrated in  FIG. 5 , the protection unit  50 C according to the third modification differs from the protection unit  50  according to the present embodiment in the structure of a reinforcing member  53 C. The reinforcing member  53 C includes a first connection member  54 C and a second connection member  55 C. 
     The first connection member  54 C is disposed inside the pair of load transmitting members  52 , and is connected to the end portions of the pair of load transmitting members  52  nearby the first housing  20 . The second connection member  55 C is disposed between the load receiving member  51  and the first connection member  54 C. The second connection member  55 C includes a first linear member  56  and a second linear member  57 . The first linear member  56  and the second linear member  57  intersect with each other inside the pair of load transmitting members  52 . 
     The first linear member  56  is connected to an end portion  521   a  of one load transmitting member  52  and an end portion  522   b  of the other load transmitting member  52 . The end portion  521   a  is connected to the load receiving member  51 , and the end portion  522   b  is connected to the first housing  20 . 
     The second linear member  57  is connected to an end portion  522   a  of one load transmitting member  52  and an end portion  521   b  of the other load transmitting member  52 . The end portion  522   a  is connected to the load receiving member  51 , and the end portion  521   b  is connected to the first housing  20 . 
     Even with the protection unit  50 C according to the third modification, it is possible to obtain substantially the same effect as that of the present embodiment. 
     Although the embodiments of the present disclosure have been described as above, it should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present disclosure is defined by the terms of the claims, and is intended to include any modifications within the meaning and scope equivalent to the terms of the claims.