Patent Publication Number: US-2022223342-A1

Title: Capacitor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation application of International Application No. PCT/JP2020/036175, filed on Sep. 25, 2020, which claims priority to Japanese Patent Application No. 2019-181861, filed on Oct. 2, 2019. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a capacitor. 
     Background Art 
     A capacitor is disclosed, the capacitor including a capacitor case having an opening portion on a first side thereof, a plurality of capacitor elements housed in the capacitor case, a pair of bus bars connected respectively to a pair of electrode surfaces of each of the capacitor elements, and a sealing member that is charged into the capacitor case through the opening portion and that seals the capacitor elements. 
     SUMMARY 
     in the present disclosure, provided is a capacitor as the following. 
     The capacitor including a capacitor element, a pair of bus bars, a capacitor case and a sealing member. The capacitor case includes a rib extended from a part of the capacitor case to an inside of the capacitor case. At least one of the pair of bus bars serves as a fixing bus bar, and the fixing bus bar includes a direct fixing portion to be directly fixed to the rib. The capacitor case includes a fixed portion for allowing the capacitor case to be fixed to another member, and the capacitor case includes a first portion where the fixed portion is formed, and the rib is formed on an inner surface of the first portion of the capacitor case. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-described object, other objects, features, and advantages of the present disclosure become more apparent in light of the following detailed description with reference to the following accompanying drawings. 
         FIG. 1  is a plan view of a capacitor according to an embodiment. 
         FIG. 2  is a cross-sectional view as viewed in a direction indicated by arrows  11 -Il in  FIG. 1 . 
         FIG. 3  is a plan view of the capacitor according to the embodiment in a state in which a sealing member is removed. 
         FIG. 4  is a plan view of a capacitor case and a fixing bus bar according to the embodiment. 
         FIG. 5  is an enlarged plan view of a vicinity of a rib of the capacitor case and a direct fixing portion of the fixing bus bar according to the embodiment. 
         FIG. 6  is an enlarged perspective view of the vicinity of the rib of the capacitor case and the direct fixing portion of the fixing bus bar according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     
         
         [PTL 1] JP 2013-161864 A 
       
    
     From a viewpoint of increasing strength of capacitors, there is still room for improvement of the capacitor disclosed in Patent Literature 1. In recent years, height reduction of capacitors, that is, thickness reduction of capacitors has been requested. Meanwhile, there is a risk that strength of capacitors is liable to decrease along with height reduction of capacitors. In view of such circumstances, in order that the request for height reduction of capacitors is satisfied, a structure in which strength of capacitors is easily secured has been demanded. 
     The present disclosure has been made to provide a capacitor for which strength is easily secured. 
     According to a first aspect of the present disclosure, there is provided a capacitor including: 
     a capacitor element that includes a pair of electrode surfaces; 
     a pair of bus bars each of which is connected to a corresponding one of the pair of electrode surfaces; 
     a capacitor case in which the capacitor element and the pair of bus bars are arranged; and 
     a sealing member that is charged in the capacitor case and that seals the capacitor element, 
     the capacitor case includes a rib extended from a part of the capacitor case to an inside of the capacitor case, 
     at least one of the pair of bus bars serves as a fixing bus bar, and the fixing bus bar includes a direct fixing portion to be directly fixed to the rib, 
     the capacitor case includes a fixed portion for allowing the capacitor case to be fixed to another member, and 
     the capacitor case includes a first portion where the fixed portion is formed, and the rib is formed on an inner surface of the first portion of the capacitor case. 
     According to a second aspect of the present disclosure, there is provided a capacitor including: 
     a capacitor element that includes a pair of electrode surfaces; 
     a pair of bus bars each of which is connected to a corresponding one of the pair of electrode surfaces; 
     a capacitor case in which the capacitor element and the pair of bus bars are arranged; and 
     a sealing member that is charged in the capacitor case and that seals the capacitor element, 
     the capacitor case includes a rib extended from a part of the capacitor case to an inside of the capacitor case, 
     at least one of the pair of bus bars serves as a fixing bus bar, and the fixing bus bar includes a direct fixing portion to be directly fixed to the rib, 
     an inner surface of the capacitor case includes a first surface portion where the rib is formed and a second surface portion which is adjacent to the first surface portion, and 
     the first surface portion is formed to be curved to protrude outward relative to the second surface portion. 
     The capacitor case of the capacitor according to the above-described aspect includes the rib extended from a part of the capacitor case to the inside of the capacitor case. Thus, strength of the capacitor case is easily increased. Further, the fixing bus bar being the at least one of the bus bars includes the direct fixing portion to be directly fixed to the rib. With this, the fixing bus bar is fixed to a portion of the capacitor case where strength is relatively easily secured. In addition, the capacitor case is reinforced by the fixing bus bar fixed to the capacitor case. In this way, overall strength of the capacitor can be secured. 
     As described above, according to the above-described aspect, the capacitor for which strength is easily secured can be provided. 
     Embodiment 
     A capacitor according to an embodiment is described with reference to  FIG. 1  to  FIG. 6 . 
     As illustrated in  FIG. 1  and  FIG. 2 , this capacitor  1  according to this embodiment includes capacitor elements  2 , a pair of bus bars  3 P and  3 N, a capacitor case  4 , and a sealing member  5 . Note that, in  FIG. 1 , positions of outlines of the capacitors  2  are indicated by broken lines. 
     As illustrated in  FIG. 2 , the capacitor elements  2  each include a pair of electrode surfaces  21 P and  21 N. The pair of bus bars  3 P and  3 N are connected to the electrode surfaces  21 P and  21 N of each of the capacitor elements  2 . The capacitor elements  2  and the pair of bus bars  3 P and  3 N are arranged in the capacitor case  4 . The sealing member  5  is charged in the capacitor case  4 . The sealing member  5  seals the capacitor elements  2 . 
     As illustrated in  FIG. 5  and  FIG. 6 , the capacitor case  4  includes a rib  40  extended from a part of the capacitor case  4  to an inside of the capacitor case  4 . The fixing bus bar  3 P, which is one of the bus bars  3 P and  3 N, includes a direct fixing portion  33  to be directly fixed to the rib  40 . The direct fixing portion  33  is fixed to the rib  40  while in direct abutment with the rib  40 . 
     Hereinbelow, the embodiment is described in detail. 
     The capacitor  1  may be, for example, a constituent part of a power conversion apparatus. The power conversion apparatus may be an in-vehicle power conversion apparatus to be mounted to vehicles such as electric vehicles and hybrid vehicles. The power conversion apparatus is arranged between a DC power supply and a three-phase AC motor (none of which is shown). The capacitor  1  smooths a DC voltage to be applied from a side where the DC power supply is present, and then outputs the smoothed DC voltage to a side where a switching circuit is present. The switching circuit converts the DC voltage to an AC voltage. The power conversion apparatus applies the AC voltage generated in this way to the three-phase AC motor. 
     The capacitor elements  2  may each be, for example, a film capacitor that is formed by winding a metallized film and that has the electrode surfaces  21 P and  21 N formed by metal spraying at both end portions in an axis direction in which the winding is performed. A plurality of capacitor elements  2  are provided as the capacitor elements  2  of the capacitor  1  according to this embodiment. Specifically, as illustrated in  FIG. 2  and  FIG. 3 , the capacitor  1  according to this embodiment is a capacitor in which arrangement of the plurality of capacitor elements  2  is contrived such that the capacitor  1  is reduced in overall height (that is, reduced in thickness). 
     As illustrated in  FIG. 2  and  FIG. 3 , in the capacitor  1  according to this embodiment, the plurality of capacitor elements  2  are arrayed in two rows along a longitudinal direction of the capacitor  1  with their electrode surfaces  21 N to serve as negative electrodes facing each other in a transverse direction of the capacitor  1 . The capacitor elements  2  are each liable to be elongated in the direction in which its pair of electrode surfaces  21 P and  21 N face each other. As a countermeasure, by adopting such arrangement, the capacitor  1  can be reduced in height. Note that, hereinbelow, a thickness direction of the capacitor  1  is referred to as a Z-direction, the longitudinal direction of the capacitor  1  is referred to as an X-direction, and the transverse direction of the capacitor  1  is referred to as a Y-direction. The plurality of capacitor elements  2  are housed in the capacitor case  4 . 
     As illustrated in  FIG. 2  and  FIG. 4 , the capacitor case  4  is formed into a shape of a box opened on a first side in the Z-direction. The capacitor case  4  is made, for example, of an electrically-insulating thermoplastic resin. The capacitor case  4  has a bottom wall  41 , a side wall  42  provided upright from the bottom wall  41 , and an opening portion  43  on a first side of the side wall  42 , the first side being opposite to a second side where the bottom wall  41  is provided. The bottom wall  41  exhibits a rectangular shape with a longitudinal direction in the X-direction and a transverse direction in the Y-direction. The side wall  42  is protruded from a periphery of the bottom wall  41  onto the first side in the Z-direction, and includes a first pair of facing wall portions being wall portions facing each other in the Y-direction, and a second pair of facing wall portions being wall portions facing each other in the X-direction. Hereinbelow, of the side wall  42 , the first pair of facing wall portions facing each other in the Y-direction are referred to as long side walls  421 , and the second pair of facing wall portions facing each other in the X-direction are referred to as short side walls  422 . The long side walls  421  are formed to extend in the X-direction, and the short side walls  422  are formed to extend in the Y-direction. A length in the X-direction of each of the long side walls  421  is larger than a length in the Y-direction of each of the short side walls  422 . 
     As illustrated in  FIG. 1  to  FIG. 4 , the side wall  42  is provided with fixed portions  44  protruding to an outside of the capacitor case  4 . The fixed portions  44  have a function to enable the capacitor case  4  to be mounted to other members. For example, the capacitor  1  is fastened with bolts through the fixed portions  44  to an apparatus case (not shown) forming an outer shell of the power conversion apparatus. 
     As illustrated in  FIG. 1 ,  FIG. 3 , and  FIG. 4 , in this embodiment, six fixed portions  44  are provided as the fixed portions  44  of the capacitor  1 . Of the six fixed portions  44 , two are provided to one of the long side walls  421 , another three are provided to another one of the long side walls  421 , and still another one is provided to one of the short side walls  422 . In this embodiment, of the pair of long side walls  421 , the long side wall  421  on which the two fixed portions  44  are formed is referred to as a first long side wall  421   a , and the long side wall  421  on which the another three fixed portions  44  are provided is referred to as a second long side wall  421   b . In addition, one side in the Y-direction, specifically, the side where the first long side wall  421   a  is provided as viewed from the side where the second long side wall  421   b  is provided is referred to as a Y 1 -side, and the side where the second long side wall  421   b  is provided as viewed from the side where the first long side wall  421   a  is provided is referred to as a Y 2 -side. The fixed portion  44  provided on the short side wall  422  is provided on an end portion on the Y 1 -side of the short side wall  422 . 
     As illustrated in  FIG. 5  and  FIG. 6 , a recessed portion  423  is formed in the first long side wall  421   a . The recessed portion  423  protrudes to an outside in the Y-direction (that is, Y 1 -side) relative to adjacent wall portions in the X-direction of the first long side wall  421   a . In this way, an inner surface of the recessed portion  423  is recessed. The recessed portion  423  is formed at the part of the first long side wall  421   a  where the fixed portion  44  is provided. The recessed portion  423  is formed all over the first long side wall  421   a  in the Z-direction. 
     In addition, the rib  40  is formed in the recessed portion  423 . Specifically, the surface portion of inner surfaces of the capacitor case  4  where the rib  40  is formed (that is, the inner surface of the recessed portion  423 ) is formed to be curved to protrude to the outside of the capacitor case  4  relative to the portions adjacent to the surface portion. The capacitor case  4  includes a wall portion where the fixed portion  44  is formed, and the rib  40  is formed on an inner surface of the wall portion of the capacitor case  4 . 
     The rib  40  is formed integrally with the first long side wall  421   a  and the bottom wall  41 . In other words, the rib  40  is formed together with the bottom wall  41 , the side wall  42 , and the like at a time of molding the capacitor case  4 . The rib  40  is formed into a shape of a plate having a thickness in the X-direction. 
     As illustrated in  FIG. 6 , the rib  40  is formed locally at an end portion of the first long side wall  421   a  in the Z-direction, the end portion being on a side where the bottom wall  41  is present. Note that, the rib  40  may be formed at other parts. In addition, as illustrated in  FIG. 2  and  FIG. 3 , the rib  40  is formed at a position facing the capacitor element  2  in the Y-direction. Specifically, at least a part of the rib  40  is arranged at a position overlapped with at least a part of the capacitor element  2  in the Y-direction. Note that, in  FIG. 2 , projections in the X-direction of shapes of an outline of the rib  40  and an outline of the direct fixing portion  33  are indicated by broken lines. In addition, as described above, the fixing bus bar  3 P is directly fixed to the rib  40 . 
     As illustrated in  FIG. 2 , the fixing bus bar  3 P is a positive bus bar to be electrically connected to the electrode surfaces  21 P on a positive side of the capacitor elements  2 . Note that, a negative bus bar to be electrically connected to the electrode surfaces  21 N on a negative side of the capacitor elements  2  may be used as the fixing bus bar. As illustrated in  FIG. 2  and  FIG. 4 , the fixing bus bar  3 P includes a bus-bar bottom surface portion  31  formed along the bottom wall  41  of the capacitor case  4 , and bus-bar side surface portions  32  extended from a first end of the bus-bar bottom surface portion  31  to the opening side in the Z-direction of the capacitor case  4 . 
     As illustrated in  FIG. 2 , the bus-bar bottom surface portion  31  is interposed between the bottom wall  41  of the capacitor case  4  and the plurality of capacitor elements  2 . The bus-bar bottom surface portion  31  is arranged to face the bottom wall  41  of the capacitor case  4  across a slight gap. With this, the sealing member  5  is arranged also in a minute region between the bus-bar bottom surface portion  31  and the bottom wall  41  of the capacitor case  4 . Although not shown, an insulating member such as an insulating sheet is arranged between the bus-bar bottom surface portion  31  and the respective electrode surfaces  21 N on the negative side of the capacitor elements  2 . In such a way, electrical insulation is secured. As illustrated in  FIG. 4  to  FIG. 6 , the direct fixing portion  33  is extended from the bus-bar bottom surface portion  31  of the fixing bus bar  3 P to the Y 1 -side. 
     The direct fixing portion  33  allows the rib  40  of the capacitor case  4  to be press-fitted therein. With this, the direct fixing portion  33  is directly fixed to the rib  40 . The direct fixing portion  33  is formed to protrude to the Y 1 -side relative to adjacent parts of the bus-bar bottom surface portion  31 . At least a part of the direct fixing portion  33  faces a part of the capacitor element  2  in the Z-direction. In other words, at least a part of the direct fixing portion  33  is arranged at a position overlapped with the capacitor element  2  in the Z-direction. 
     As illustrated in  FIG. 5  and  FIG. 6 , at a Y 1 -side end portion of the direct fixing portion  33 , a pair of first parts  331  extended from both end portions in the X-direction of the direct fixing portion  33  to the Y 1 -side, and a pair of second parts  332  extended from respective end portions on the Y 1 -side of the first parts  331  to sides facing each other are provided. The pair of second parts  332  are formed to face each other across a gap in the X-direction. In addition, the rib  40  is press-fitted in the gap between the pair of second parts  332 . With this, the fixing bus bar  3 P and the rib  40  are directly fixed to each other. 
     At parts of the bus-bar bottom surface portion  31  which are adjacent to both sides of the rib  40  in the X-direction, slits  34  which are formed in a manner that an edge on the Y 1 -side of the bus-bar bottom surface portion  31  is recessed to the Y 2 -side are provided. By forming these slits  34 , in forming the fixing bus bar  3 P, for example, by bending a flat sheet metal, the direct fixing portion  33  can be prevented from being deformed in conjunction with bending of boundary portions between the bus-bar side surface portion  32  and the bus-bar bottom surface portion  31 , the boundary portions being adjacent to the direct fixing portion  33 . 
     As illustrated in  FIG. 2  and  FIG. 4 , of the pair of bus-bar side surface portions  32  formed on both sides in the Y-direction, a first bus-bar side surface portion  32  formed on the Y 1 -side faces an inner surface of the first long side wall  421   a , and a second bus-bar side surface portion  32  formed on the Y 2 -side faces an inner surface of the second long side wall  421   b . With this, as illustrated in  FIG. 2 , the bus-bar bottom surface portion  31  and the bus-bar side surface portions  32  on both the sides in the Y-direction of the fixing bus bar  3 P has a U-shape as viewed in the X-direction. 
     As illustrated in  FIG. 2  and  FIG. 3 , the capacitor elements  2  are arrayed in the two rows which are the Y 1  side row and the Y 2  side row. The capacitor elements  2  constituting the Y 1  side row serve as a first-row element group  201  and the capacitor elements  2  constituting the Y 2  side row serve as a second-row element group  202 . The first bus-bar side surface portion  32  is connected to the respective electrode surfaces  21 P on the Y 1 -side of the first-row element group  201 . The second bus-bar side surface portion  32  is connected to the respective electrode surfaces  21 P on the Y 2 -side of the second-row element group  202 . Note that, unlike the bus-bar side surface portions  32 , the direct fixing portion  33  is not connected to the capacitor elements  2 . 
     As illustrated in  FIG. 4 , bus-bar terminal portions  35 P for allowing the fixing bus bar  3 P to be electrically connected to switching elements of the switching circuit in the power conversion apparatus are extended from the second bus-bar side surface portion  32 . In other words, as viewed from the opening side in the Z-direction of the capacitor case  4 , the bus-bar terminal portions  35 P are formed in a region on the side opposite to the side where the direct fixing portion  33  is formed. As illustrated in  FIG. 2 , the bus-bar terminal portions  35 P project to the opening side in the Z-direction of the capacitor case  4 , and are formed farther to the Y 2 -side than the capacitor case  4  extends. 
     As illustrated in  FIG. 2 , the bus bars  3 N, which are negative, are connected to the respective electrode surfaces  21 N on the negative side of the capacitor elements  2  (that is, the electrode surfaces  21 N facing the second-row element group  202 , of the electrode surfaces  21 P and  21 N of the capacitor elements  2  constituting the first-row element group  201 , and the electrode surfaces  21 N facing the first-row element group  201 , of the electrode surfaces  21 P and  21 N of the capacitor elements  2  constituting the second-row element group  202 ). In this embodiment, a first negative bus bar  3 N and a second negative bus bar  3 N are arranged as the negative bus bars  3 N. The first negative bus bar  3 N is connected to the respective electrode surfaces  21 N on the negative side of the plurality of capacitor elements  2  constituting the first-row element group  201 , and the second negative bus bar  3 N is connected to the respective electrode surfaces  21 N on the negative side of the plurality of capacitor elements  2  constituting the second-row element group  202 . 
     The first negative bus bar  3 N and the second negative bus bar  3 N are arranged in a manner of being overlapped with each other in the Z-direction at a position on the opening side of the capacitor case  4  in the Z-direction of the second-row element group  202 . 
     Bus-bar terminal portions  35 N for respectively allowing the negative bus bars  3 N to be electrically connected to the switching elements are formed on respective first sides of the negative bus bars  3 N, the first sides each being opposite to a second side which is connected to the capacitor elements  2 . The bus-bar terminal portions  35 N project to the opening side of the capacitor case  4  in the Z-direction, and are formed farther to the Y 2 -side than the capacitor case  4  extends. Two bus-bar terminal portions  35 N are provided as the bus-bar terminal portions  35 N of each of the negative bus bars  3 N, and the bus-bar terminal portions  35 N of each of the negative bus bars  3 N are arranged in the manner of being overlapped with each other in the Z-direction. 
     As illustrated in  FIG. 3 , regions on both sides of a center position “c” between the pair of long side walls  421  in a direction (that is, Y-direction) in which the pair of long side walls  421  face each other include a first region and a second region, the first region having fewer fixed points  6  for an external member than the second area, and the rib  40  and the direct fixing portion  33  are located in the first region. In this embodiment, in the region on the Y 1 -side relative to the center position “c”, there are three fixed portions  44  for allowing the capacitor case  4  to be fixed to the apparatus case of the power conversion apparatus. Meanwhile, in a region on the Y 2 -side relative to the center position “c”, in addition to three fixed portions  44 , the bus-bar terminal portions  35 P and  35 N for allowing the bus bars  3 P and  3 N to be connected to other members (such as bus bars (not shown) for allowing the capacitor  1  and the switching elements to be connected to each other) are formed at four points. In other words, in the region on the Y 2 -region relative to the center position “c” the fixation points  6  for allowing the capacitor  1  to be fixed to other members are present at seven points. In addition, in this embodiment, the rib  40  and the direct fixing portion  33  are arranged in the region on the Y 1 -side relative to the center position “c”. 
     Although not shown, an insulating member for securing electrical insulation between the fixing bus bar  3 P and the negative bus bars  3 N is arranged in a region where the fixing bus bar  3 P and the negative bus bars  3 N are electrically close to each other (for example, between the bus-bar terminal portions  35 P of the fixing bus bar  3 P and the bus-bar terminal portions  35 N of the negative bus bars  3 N). As illustrated in  FIG. 1  and  FIG. 2 , the sealing member  5  is charged in the capacitor case  4 . 
     The sealing member  5  is made, for example, of an electrically-insulating thermosetting resin. The sealing member  5  under a low-temperature fluidized state is charged into the capacitor case  4 , and then is cured by being heated. An end portion of the sealing member  5  on the opening side of the capacitor case  4  is formed at a position equivalent to that of the opening portion  43  of the capacitor case  4 . The sealing member  5  seals the plurality of capacitor elements  2 . With this, humidity resistance of the capacitor elements  2  is secured. 
     Further, as illustrated in  FIG. 3  and  FIG. 4 , a plurality of through-holes  30  for allowing the fluidized sealing member  5  to pass therethrough are formed through each of the bus bars (specifically, fixing bus bar  3 P and two negative bus bars  3 N). In other words, although the sealing member  5  is viscous to some extent in being charged into the capacitor case  4 , the through-holes  30  provided through the bus bars  3 P and  3 N facilitates a spread of the sealing member  5  throughout the inside of the capacitor case  4 . 
     Now, functions and advantages of this embodiment are described. 
     The capacitor case  4  of the capacitor  1  according to this embodiment includes the rib  40  extended from part of the capacitor case  4  to the inside of the capacitor case  4 . Thus, strength of the capacitor case  4  is easily increased. Further, the fixing bus bar  3 P, being the at least one of the bus bars  3 P and  3 N, includes the direct fixing portion  33  to be directly fixed to the rib  40 . With this, the fixing bus bar  3 P is fixed to a portion of the capacitor case  4  where strength is relatively easily secured. In addition, the capacitor case  4  is reinforced by the fixing bus bar  3 P fixed to the capacitor case  4 . In this way, strength of the capacitor  1  as a whole can be secured. Still further, the sealing member  5  is interposed between the fixing bus bar  3 P and the capacitor case  4 . With this, a degree of the reinforcement of the capacitor case  4  by the fixing bus bar  3 P can be increased. At this time, since the fixing bus bar  3 P is directly fixed to the capacitor case  4 , the capacitor elements  2  can be accurately positioned relative to the capacitor case  4 . 
     Yet further, the capacitor case  4  includes a first portion where the fixed portion  44  is formed, and the rib is formed on the inner surface of the first portion of the capacitor case  4 . Thus, heat of the capacitor elements  2  is easily dissipated to the outside of the capacitor case  4 . Specifically, during use of the capacitor  1 , the heat of the capacitor elements  2  is easily dissipated from the fixed portion  44  to the outside of the capacitor  1  via the fixing bus bar  3 P, the direct fixing portion  33  of the fixing bus bar  3 P, the rib  40 , and a part of the capacitor case  4 . Yet further, the portion of the capacitor case  4  where the fixed portions  44  are formed is relatively easy to secure strength. Thus, by providing, at such a portion, the rib  40  for allowing the direct fixing portion  33  of the fixing bus bar  3 P to be fixed, the fixing bus bar  3 P is easily fixed to the capacitor case  4  more firmly. With this, strength of the capacitor  1  as a whole can be further secured. 
     Yet further, the surface portion of inner surfaces of the capacitor case  4  where the rib  40  is formed, is formed to be curved to protrude to the outside of the capacitor case  4  relative to the portions adjacent to the surface portion. Thus, stiffness of a wall portion of the capacitor case  4  where the rib  40  is formed, is easily increased. In addition, the fixing bus bar  3 P can be fixed to the capacitor case  4  more firmly. With this, the strength of the capacitor  1  as a whole can be further secured. In addition, since the rib  40  is provided in the recessed portion  423  formed to protrude to the outside of the capacitor case  4 , the rib  40  does not obstruct the capacitor elements  2  to be housed in the capacitor case  4 . 
     Yet further, the side wall  42  of the capacitor case  4  includes the pair of long side walls  421  facing each other, and an at least one of the long side walls  421  includes the fixed portions  44  for allowing the capacitor case  4  to be fixed to the other members. Yet further, the rib  40  and the direct fixing portion  33  are located in the first region of regions on both sides of the center position “c” between the pair of long side walls  421  in the direction in which the pair of long side walls  421  face each other (that is, Y-direction), the first region being on the side where fixation points  6  for external members is few. In this context, it is relatively difficult to secure strength in the first region. As a countermeasure, in the region of the capacitor  1  where it is relatively difficult to secure strength, the fixing bus bar  3 P is directly fixed to the rib  40  of the capacitor case  4 . With this, stiffness of the capacitor  1  is easily increased in the above region. As a result, the stiffness of the capacitor  1  is easily secured in the entire capacitor  1 . 
     Yet further, as viewed from the opening side of the capacitor case  4 , the direct fixing portion  33  is located on a region of the fixing bus bar  3 P on the side opposite to the side where the bus-bar terminal portions  35 P are formed. Thus, the fixing bus bar  3 P is fixed to the other members via the bus-bar terminal portions  35 P at one end, and fixed to the rib  40  of the capacitor case  4  via the direct fixing portion  33  at another end. With this, strength of the fixing bus bar  3 P as a whole is increased, and hence strength of the capacitor  1  as a whole is further secured by the fixing bus bar  3 P. 
     Yet further, the fixing bus bar  3 P is arranged along the bottom wall  41  of the capacitor case  4 . This enables the bottom wall  41  of the capacitor  1  to be reinforced by the fixing bus bar  3 P, and hence strength of the capacitor  1  as a whole is easily secured. 
     Yet further, the fixing bus bar  3 P includes the bus-bar bottom surface portion  31  along the bottom wall  41  of the capacitor case  4 , and the bus-bar side surface portions  32  extending from the bus-bar bottom surface portion  31  and along the side wall  42  of the capacitor case  4 . With this, the entire capacitor case  4  is easily reinforced, and strength of the capacitor  1  as a whole is more easily secured. 
     Yet further, an at least one of the rib  40  and the direct fixing portion  33  is provided at the position facing the capacitor elements  2 . Thus, thermal distance from the capacitor elements  2  to the rib  40  and the direct fixing portion  33  is easily reduced, and hence the heat of the capacitor elements  2  is easily dissipated to the capacitor case  4  via the fixing bus bar  3 P and the rib  40 . 
     As described above, according to this embodiment, the capacitor for which strength is easily secured can be provided. 
     Modifications 
     The present disclosure is not limited to the embodiment described hereinabove, and is applicable to various embodiments without departing from the gist thereof. 
     For example, although the bus bar on the positive side is used as the fixing bus bar in the embodiment described hereinabove, the bus bars on the negative side (negative bus bars  3 N according to the embodiment described hereinabove) may each be used as the fixing bus bar. Alternatively, both the bus bars on the positive side and the bus bars on the negative side may each be used as the fixing bus bar. 
     Further, the rib need not necessarily be locally formed at the end portion of the first long side wall in the Z-direction as in the embodiment described hereinabove, the end portion being on the side where the bottom wall is present. The rib may be formed all over the first long side wall in the Z-direction. Alternatively, the rib may be formed only on the side wall or only on the bottom wall. 
     Still alternatively, the shapes of the rib and the fixing bus bar are not limited as long as the fixing bus bar are directly fixed to the rib (that is, as long as the fixing bus bar includes the direct fixing portion). For example, the rib may include a portion provided to the fixing bus bar in a manner opposite to the opening side of the capacitor case in the Z-direction. In this case, the rib may be formed into a hook shape (inverted L-shape), a T-shape, or the like. In this case, the fixing bus bar can be prevented from floating in charging the sealing member into the capacitor case. 
     It should be understood that the present disclosure, which has been described with reference to the embodiment, is not limited to the embodiment or structures. The present disclosure also encompasses various modifications and equivalents. In addition, various combinations and forms or other combinations and forms including only one additional element, two or more additional elements, or a portion of one additional element are also included in the scope of the present disclosure or the range of ideas.