Patent Publication Number: US-2021167468-A1

Title: Power storage component module

Description:
TECHNICAL FIELD 
     The technology disclosed herein relates to a power storage component module, specifically to a structure for connecting power storage component to one another. 
     BACKGROUND ART 
     An example of a power storage component module that includes power storage components disclosed in Patent Document 1 has been known. In the power storage component module, each of battery packs includes electric terminals and bus bars. The electric terminals include upper surfaces that are flat and defined as electrode surfaces. The bus bars formed from plates. Each bus bar has a rectangular shape. The battery packs are arranged such that adjacent electric terminals have opposite polarities. A wire module is attached to surfaces on which the electric terminals are disposed. The bus bars and the electric terminals disposed inside the wire module are electrically connected by laser welding portions of the bus bars placed over the electrical terminals to the electric terminals. 
     RELATED ART DOCUMENT 
     Patent Document 
     [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2016-100248 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     According to the technology, the electric terminals must have surface contact with the bus bars. If vertical positions of the surfaces of the adjacent battery packs on which the electric terminals are disposed are different from each other due to dimensional differences within tolerance, the bus bars need to be forcedly brought into surface contact with the electric terminals for joint. This may result in plastic deformation of the bus bars. 
     Means for Solving the Problem 
     A power storage component module according to the technology described herein includes a first power storage component, a second power storage component, and a bus bar. The first power storage component is disposed with an electrode of the first power storage component facing up. The second power storage component is disposed with an electrode of the second power storage component facing up. The bus bar connects the first power storage component and the second power storage component together. The first power storage component includes a positioning boss projecting upward from the electrode of the first power storage component. The bus bar includes: a through hole opening in a top-bottom direction and through which the positioning boss is passed; and a support projection projecting downward, the support projection being disposed on the electrode of the first power storage component. The support projection is electrically connected to the electrode of the first power storage component via a joint between the support projection and the electrode. The joint and the positioning boss are aligned when viewed from above. 
     According to the configuration, the bus bar can be positioned relative to the positioning boss by passing the positioning boss through the through hole and placing the support projection on the electrodes. When the support projection is place on the electrode, the bus bar tilts due to its own weight and contacts the electrodes. According to the configuration, even if a difference in vertical position is present between the electrode of the first power storage component and the electrode of the second power storage component, the bus bar is disposed on the electrodes at an angle regardless of the difference. Therefore, the bus bar is less likely to deform and thus the durability of the bus bar is ensured. Further, the joint and the positioning boss are aligned when viewed from above, that is, a position at which the joint is formed can be determined based on the positioning boss. 
     Preferable embodiments of the technology described herein may have the following configurations. 
     (1) The support projection may include a distal end that is aligned with the positioning boss. The electrode may include a holding section on which the distal end is disposed. The joint may include the distal end and the holding section. 
     According to the configuration, to form the joint, positions of the distal end and the holding section are determined based on the positioning boss and a portion in which the joint is to be formed is defined based on the positions. 
     (2) The distal end may have a linear shape. The bus bar may include a V-shaped groove in an upper surface of the bus bar over the supporting projection. The V-shaped groove may be recessed to form a V shape when viewed from a side. The V-shaped groove may include a groove bottom having a linear shape. The groove bottom may overlap the distal end in the top-bottom direction. 
     According to the configuration, the position of the distal end can be determined from above based on detection of the groove bottom from above. Therefore, the portion in which the joint is to be formed can be determined as a linear portion, that is, an area in which joining is performed can be reduced. Further, the V-shaped groove and the support projection are formed by bending the bus bar so that the distal end projects downward. This reduces a process cost. 
     (3) The support projection may have a spherical dome shape. The support projection may include a spherical dome recess having a spherical shape in an upper surface of the bus bar. The spherical dome recess may be concentric with the support projection. 
     According to the configuration, the lowest section of the support projection is the distal end. Further, the distal end and the lowest section of the spherical dome recess are aligned in the top-bottom direction. Therefore, a position of the lowest section on the upper surface side can be determined as a position of the distal end. From the determination, the area in which joining is performed can be determined. 
     Advantageous Effects of Invention 
     According to the technology disclosed herein, durability of the bus bar improves. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a power storage component module according to a first embodiment. 
         FIG. 2  is a perspective view illustrating a power storage component. 
         FIG. 3  is a side view illustrating a power storage component module. 
         FIG. 4  is a perspective view illustrating a bus bar. 
         FIG. 5  is a top view illustrating the bus bar. 
         FIG. 6  is a side view illustrating the bus bar. 
         FIG. 7  is a top view illustrating the power storage component module. 
         FIG. 8  is a cross-sectional view along line A-A in  FIG. 7 . 
         FIG. 9  is a perspective view illustrating a bus bar according to a second embodiment. 
         FIG. 10  is a side view illustrating the bus bar. 
         FIG. 11  is a rear view illustrating a power storage component module. 
         FIG. 12  is a top view illustrating the power storage component module. 
         FIG. 13  is a side view illustrating the power storage component module. 
         FIG. 14  is a side view illustrating a power storage component module according to a third embodiment. 
         FIG. 15  is a perspective view illustrating the power storage component module. 
         FIG. 16  is a top view illustrating the power storage component module. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     First Embodiment 
     A first embodiment will be described with reference to  FIGS. 1 to 8 . 
     This embodiment relates to a power storage component module  1  to be installed in a vehicle. As illustrated in  FIG. 1 , the power storage component module  1  includes multiple (two in this embodiment) power storage components  10  and  110  and a bus bar  30  that connects the power storage component  10  to the power storage component  110 . The embodiment will be described with reference to a Z arrow, a Y arrow, and an X arrow that point an upper side, a front side, and a left side, respectively. 
     As illustrated in  FIG. 2 , the first power storage component  10  of the power storage components  10  and  110  includes a component body  11  and an electrode  12 . The component body  11  has a box shape that is flat in a front-rear direction. The electrode  12  is disposed on an upper surface of the component body  11 . An upper surface  12 A of the electrode  12  is a flat surface. The upper surface  12 A of the electrode  12  may be referred to as an electrode surface  12 A hereinafter. 
     The first power storage component  10  includes a positioning boss  20  for positioning the bus bar  30  relative to the electrode  12 . The positioning boss  20  is made of a conductive metal material. The positioning boss  20  protrudes upward from the electrode  12 . The positioning boss  20  includes a base end  20 B and an upper end  20 D. The base end  20 B has a round shape in a top view. The upper end  20 D has a round shape that is concentric with the base end  20 B. The positioning boss  20  has a truncated cone shape with a diameter that slightly decreases from the base end  20 B toward the upper end  20 D. The second power storage component  110  includes an electrode  12  that has an opposite polarity from a polarity of the electrode of the first power storage component  10 . Other configurations of the second power storage component  110  are similar to those of the first power storage component  10  and thus will not be described. 
     As illustrated in  FIG. 1 , the first power storage component  10  and the second power storage component  110  are disposed inside a module case, which is not illustrated, with the electrode surfaces  12 A arranged in the front-rear direction. The electrode surface  12 A of the first power storage component  10  and an electrode surface  12 A of the second power storage component  110  may be at different vertical positions because of positioning errors that are allowed within the dimensional tolerance of the first storage component  10 , the second power storage component  110 , and the module case. In this embodiment, as illustrated in  FIG. 3 , the electrode surface  12 A of the first power storage component  10  is positioned lower than the electrode surface  12 A of the second power storage component  110 . The positioning errors of the first power storage component  10  and the second power storage component  110  in the top-bottom direction are assumed to be the maximum. 
     The bus bar  30  is made of a conductive metal material such as copper and aluminum. As illustrated in  FIGS. 4 and 5 , the bus bar  30  has a rectangular plate shape in a top view. The bus bar  30  includes two through holes  40  that open in a direction normal to a plate surface of the bus bar  30 . 
     Specifically, as illustrated in  FIG. 5 , each through hole  40  has an oval shape that is elongated in the front-rear direction. A hole edge  41  includes an edge-side arc section  41 F, a center-side arc section  41 B, and right and left linear hole edge sections  41 S. The right and the left linear hole edge sections  41 S connect right and left rear edges of the edge-side arc section  41 F to right and left front edges of the center-side arc section  41 B. The linear hole edge sections  41 S linearly extend to be parallel to each other. A distance between the linear hole edge sections  41 S in the right-left direction (that is, a maximum width of the through hole  40 ) is defined equal to or slightly greater than a diameter of the base end  20 B of the positioning boss  20 . 
     As illustrated in  FIG. 4 , the bus bar  30  includes a connecting portion  31  and bent portions  50 . The connecting portion  31  is located in the middle with respect to the front-rear direction. The bent portions  50  are located on the front side and the rear side, respectively. Each bent portion  50  is bent to form a shallow V shape in a side view. 
     Each bent portion  50  includes a top surface that is recessed downward to form V-shaped grooves  51 . The V-shaped grooves  51  include groove bottoms  51 A that linearly extends in the right-left direction from the middle points of the corresponding linear hole edge sections  41 S with respect to the front-rear direction to right and left side edges  30 S of the bus bar  30 , respectively. Each bent portion  50  includes a lower surface that projects downward to form elongated projections that are defined as support projections  52 . The support projections  52  include upper ends  20 D that extend in the right-left direction. As illustrated in  FIG. 6 , when the bus bar  30  is in a horizontal position with a middle portion of the bus bar  30  leveled, the groove bottom  51 A of each V-shaped groove  51  is over a distal end  52 A of the corresponding support projection  52 . 
     As illustrated in  FIG. 3 , when the power storage components  10  and  110  are connected to each other with the bus bar  30 , the positioning bosses  20  are passed through the respective through holes  40  and the support projections  52  are disposed on the electrode surfaces  12 A, respectively. The bus bar  30  is positioned relative to the electrodes  12 . The arcs of each end-side arc section  41 F and each center-side arc section  41 B and the length of each liner hole edge section  41 S are defined such that the arc sections  41 F and  41 B do not contact the periphery  20 R of the corresponding positioning boss  20  even if the positioning error in the top-bottom direction between the first power storage component  10  and the second power storage component  110  is at the minimum or the maximum. As illustrated in  FIG. 7 , the end-side arc section  41 F and the center-side arc section  41 B of the hole edge  41  of each through hole  40  are separated from the periphery  20 R of the corresponding positioning boss  20  in the front-rear direction and slightly separated from the periphery  20 R in the right-left direction. 
     The electrode  12  of the first power storage component  10  and the electrode surface  12 A of the second power storage component  110  are at different vertical positions as described below. Therefore, as illustrated in  FIG. 3 , the bus bar  30  disposed on the electrode surfaces  12 A is sloped downward toward the rear. As illustrated in  FIG. 3 , a dimension of each support projection  52  that projects from the bus bar  30  is defined such that the bus bar  30  is positioned at a vertical position at which the bus bar  30  does not contact the component body  11  and the electrodes  12  of the first power storage component  10  and a component body  11  and the electrode  12  of the second power storage component  110 . 
     In the situation described above, the power storage components  10  and  110  are displaced from each other in the vertical direction. In this embodiment, each positioning boss  20  has a truncated cone shape and each through hole  40  has the oval shape that is elongated in the arrangement direction of the through holes  40 . Therefore, deviations of the power storage components  10  and  110  in the right-left direction and the front-rear direction are allowed. 
     As illustrated in  FIGS. 7 and 8 , supplemental joints  60  are formed between the linear hole edge sections  41 S of the hole edges  41  and the peripheries  20 R of the positioning bosses  20 . Two supplemental joints  60  are provided for each positioning boss  20  to electrically connect the linear hole edge sections  41 S to the periphery  20 R of the positioning boss  20 . Two supplemental joints  60  are disposed on a straight line extending in the right-left direction with the corresponding positioning boss  20  between the supplemental joints  60 . In this embodiment, each supplemental joint  60  is formed by melting surfaces of the corresponding linear hole edge section  41 S and the periphery  20 R of the corresponding positioning boss  20  through laser welding. 
     As illustrated in  FIG. 8 , joints  70  are provided between the electrode surfaces  12 A and the upper ends  20 D of two support projections  52  on the electrode surfaces  12 A. Two joints  70  are disposed on a straight line extending in the right-left direction with the corresponding positioning boss  20  between the joints  70 . In this embodiment, each joint  70  is formed by melting surfaces of a holding section  12 B of the corresponding electrode surface  12 A on which a distal end  52 A is disposed and the distal end  52 A of the corresponding support projection  52  through laser welding. 
     Next, an example of procedure of forming the joints  70  will be described. First, the bus bar  30  is disposed on the electrode surfaces  12 A of the first power storage component  10  and the second power storage component  110  held in a module case, which is not illustrated. When the positioning bosses  20  are passed through the respective through holes  40 , the bus bar  30  is sloped downward toward the rear with its own weight. According to the configuration, the distal ends  52 A of the support projections  52  are disposed on the electrode surfaces  12 A with the distal ends  52 A in contact with the electrode surfaces  12 A for entire dimensions in the right-left direction regardless of a difference in vertical position between the electrode surfaces  12 A. 
     Next, positions of the distal ends  52 A of the support projections  52  are determined. First, an existing area in which the upper ends  20 D of the positioning bosses  20  are present is detected by a detector, which is not illustrated. Then, an area obtained by expanding the existing area in the right-left direction by the width of the bus bar is defined as a possible existing area in which the distal ends  52 A may be present. Positions of the groove bottoms  51 A of the V-shaped grooves  51  in the possible existing area are detected and determined as positions of the distal ends  52 A. Areas that extend in the right-left direction to pass the positions are determined as laser application areas. 
     If the vertical positions of the electrode surfaces  12 A are different from each other, axes  52 X of the support projections  52  are slightly tilted toward the rear relative to normal lines  12 X (see  FIG. 3 ). The position of each distal end  52 A with respect to the front-rear direction and the position of the corresponding groove bottom  51 A with respect to the front-rear direction are slightly different from each other. With consideration of the difference, it is preferable that the laser application areas have margins in the front-rear direction. 
     The laser application areas are linearly scanned with laser spotlight, which is not illustrated, in the right-left direction from the top. As described earlier, the distal ends  52 A of the support projections  52  contact the electrode surfaces  12 A for entire dimensions in the right-left direction because of the weight of the bus bar  30 . Therefore, it is not necessary to press the distal ends  52 A against the electrode surfaces  12 A and thus the bus bar  30  is less likely to be deformed during forming of the joints  70 . 
     As illustrated in  FIG. 8 , surfaces of the distal ends  52 A of the support projections  52  are welded to the holding section  12 B of each electrode surface  12 A. Two joints  70  are formed such that the joints  70  are aligned with the corresponding positioning boss  20  that are between the joints  70 . 
     In the laser application areas, if distances between the linear hole edge sections  41 S and the peripheries  20 R of the respective positioning bosses  20  are within a range for the laser welding, the surfaces of the liner hole edge sections  41 S are welded to the peripheries  20 R of the respective positioning bosses  20 . Through the welding, the supplemental joints  60  are formed. As illustrated in  FIG. 8 , the supplemental joints  60  and the joints  70  are aligned in the right-left direction. 
     The power storage component module  1  includes the first power storage component  10 , the second power storage component  110 , and the bus bar  30 . The first power storage component  10  and the second power storage component  110  are disposed with the electrodes  12  on the upper side. The bus bar  30  connects the first power storage component  10  and the second power storage component  110  together. The first power storage component  10  includes the positioning boss  20  that protrudes upward from the electrode  12 . The bus bar  30  includes the through hole  40  that opens in the top-bottom direction and through which the positioning boss  20  is passed. The bus bar  30  includes the support projection  52  that projects downward. The support projection  52  is disposed on the electrode  12  of the first power storage component  10 . The joint  70  is provided between the support projection  52  and the electrode  12  of the first power storage component  10 . The joint  70  electrically connects the support projection  52  to the first power storage component  10 . The joint  70  and the positioning boss  20  are aligned when viewed from above. 
     According to the configuration, the bus bar  30  is positioned relative to the positioning boss  20  when the positioning boss  20  is passed through the through hole  40  and the support projection  52  is disposed on the electrode  12 . With the support projection  52 , the bus bar  30  tilts due to its own weight and contacts the electrodes  12 . Even if a difference is present between the vertical position of the electrode  12  and the vertical position of the electrode of the second power storage component  110 , the bus bar  30  is disposed on the electrodes  12  at an angle regardless of the difference. According to the configuration, the bus bar  30  is less likely to deform and thus the durability of the bus bar  30  is ensured. Further, the joints  70  are aligned with the positioning bosses  20 . Therefore, the positions of the joints  70  are determined based on the positioning bosses  20 . 
     The support projections  52  include the distal ends  52 A that are aligned with the positioning bosses  20 . The electrodes  12  include the holding sections  12 B on which the distal ends  52 A are placed. The joints  70  include the distal ends  52 A and the holding sections  12 B. 
     According to the configuration, to form the joints  70 , the positions of the distal ends  52 A and the holding sections  12 B are determined based on the positioning bosses  20  and portions in which the joints  70  are to be formed are defined based on the positions. 
     The distal ends  52 A are linear. The V-shaped grooves  51  including the groove bottoms  51 A that are linear are formed in the upper surface over the support projections  52 . Each V-shaped groove  51  is recessed to form the V-shape when viewed from a side. The groove bottoms  51 A overlap the respective distal ends  52 A in the top-bottom direction. 
     According to the configuration, a position  2051 A of each distal end  52 A can be determined from above based on detection of the corresponding groove bottom  51 A from above. Therefore, the portion in which the corresponding joint is to be formed can be determined as a liner portion, that is, an area in which joint forming is performed can be reduced. Further, the V-shaped grooves  51  and the support projections  52  are formed by bending the bus bar  30  so that the distal ends  52 A project downward. This reduces a processing cost. 
     Second Embodiment 
     Next, a second embodiment will be described with reference to  FIGS. 9 to 13 . This embodiment includes a power storage component module  1001  that includes a bus bar  1030  having a configuration different from the configuration of the bus bar in the first embodiment. Components and portions corresponding to those of the first embodiment may be indicated by symbols with 1000 added to the symbols that indicate the components and the portions in the first embodiment. Configurations, functions, and effects similar to those of the first embodiment will not be described. Components and portions that are the same as the first embodiment may be indicated by the symbols used for the first embodiment. 
     As illustrated in  FIGS. 9 to 11 , the bus bar  1030  in this embodiment includes recesses  1050  instead of the bent portions  50  of the bus bar  30  in the first embodiment. Two of the recesses  1050  are provided for each through hole  40  such that the recesses  1050  are on the right and the left of the through hole  40 . The recesses  1050  include support projections  1052  that project downward from a lower surface of the bus bar  1030 . Each support projection  1052  has a spherical dome shape. The recesses  1050  include spherical dome recesses  1051  in an upper surface of the bus bar  1030 . As illustrated in  FIG. 10 , each spherical dome recess  1051  has a spherical dome shape that is concentric with the support projection  1052 . 
     When the power storage components  10  and  110  are connected by the bus bar  1030 , as illustrated in  FIGS. 11  and  12 , the support projections  1052  on the right and the left are disposed on the electrode surfaces  12 A with the distal ends  1052 A in contact with the electrode surfaces  12 A on either side of the respective positioning bosses  20 . Two joints  1070  are aligned with the corresponding positioning boss  20  with the corresponding positioning boss  20  between the joints  1070 . 
     As illustrated in  FIG. 13 , the bus bar  30  is sloped downward toward the rear over the electrode surfaces  12 A. As illustrated in  FIG. 13 , the recesses  1050  contact the electrode surfaces  12 A with the lowest portions (i.e., the distal ends  1052 A) of the recesses  1050  more to the rear than centers P 1  of lower surfaces of the corresponding recesses  1050 . In this embodiment, each distal end  1052 A is movable in the front-rear direction with the center P 1  as a center of movement in response to an angle of the bus bar  1030  relative to the corresponding electrode surface  12 A. 
     To form each joint  1070 , the lowest portion of the spherical dome recess  1051  is detected by measuring from above and the lowest portion is defined as a recess bottom  1051 A (see  FIG. 13 ). A small circular area having the recess bottom  1051 A as a center is defined as a laser application area. Laser spotlight is applied to the laser application area. As illustrated in  FIGS. 12 and 13 , each joint  1070  is formed. Each spherical dome recess  1051  is concentric with the corresponding support projection  1052 . Therefore, the position of the distal end  1052 A is vertically aligned with the lowest portion (the recess bottom  1051 A) of the spherical dome recess  1051 . It is not necessary to set the laser application area with a margin in consideration of the positional difference. 
     According to the configuration, the distal end  1052 A of each support projection  1052  has a small circular shape and thus the laser application area is further limited to a smaller area. The distal end  1052 A of each support projection  1052  overlaps the corresponding recess bottom  1051 A in the top-bottom direction. Because the distal end  1052 A of each support projection  1052  overlap the corresponding recess bottom  1051 A in the top-bottom direction, the corresponding joint  1070  is properly formed through application of the laser spotlight to the laser application area. 
     Third Embodiment 
     A third embodiment will be described with reference to  FIGS. 14 to 16 . This embodiment includes a power storage component module  2001  that includes a bus bar  2030  having configuration different from the configuration of the bus bar in the first embodiment. Components and portions corresponding to those of the first embodiment may be indicated by symbols with 2000 added to the symbols that indicate the components and the portions in the first embodiment. Configurations, functions, and effects similar to those of the first embodiment will not be described. Components and portions that are the same as the first embodiment may be indicated by the symbols used for the first embodiment. 
     As illustrated in  FIG. 14 , the bus bar  2030  in this embodiment includes support projections  2052 . Each support projection  2052  has an arc shape that projects downward when viewed from a side. The bus bar  2030  includes round recesses  2051  in an upper surface over the support projections  2052 , respectively. Each round recess  2051  is recessed downward such that an arc of the round recess  2051  in a side view is concentric with an arc of the corresponding support projection  2052 . 
     According to the configuration, a distal end  2052 A of each support projection  2052  is movable in the front-rear direction with a center line L 1  of the support projection  2052  at the middle in the front-rear direction as a center of movement in response to an angle of the bus bar  2030 . Further, the distal end  2052 A of each support projection  2052  is vertically aligned with the lowest position  2051 A of the corresponding round recess  2051 . It is not necessary to set the laser application area with margins in the front-rear direction in consideration of the positional difference. 
     Other Embodiments 
     The technology disclosed herein is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments will be included in the technical scope of the technology. 
     (1) In the above embodiment, each positioning boss  20  has the truncated cone shape with the diameter that slightly decreases from the base end  20 B toward the upper end  20 D. However, the shape of the positioning bosses is not limited to the truncated cone shape. For example, each positioning boss may have a round columnar shape with a constant diameter from a base end toward an upper end. 
     (2) In the above embodiment, the positioning bosses  20  are disposed on the electrodes  12  of the power storage components  10  and  110  and the bus bar  30  includes the through holes  40 . However, a configuration that includes a positioning boss disposed on one of power storage components and a bus bar including a single through hole may be included in the technical scope. With such a configuration, a position at which a joint is formed may be determined based on detection of a position of a distal end of a support projection from above or the positioning boss. 
     (3) In the above embodiment, the surface of the distal end  52 A of each support projection  52  is welded to the holding section  12 B of the corresponding electrode surface  12 A to form the joint through the laser welding. However, the joint may be formed by placing a joining material such as a silver-based filler and a solder between the distal end and the holding section and forming the joint through brazing. 
     EXPLANATION OF SYMBOLS 
     
         
         
           
               1 ,  1001 ,  2001 : Power storage component module 
               10 : First power storage component 
               12 : Electrode 
               12 B: Holding section 
               20 : Positioning boss 
               30 ,  1030 ,  2030 : Bus bar 
               40 : Through hole 
               51 : V-shaped groove 
               51 A: Groove bottom 
               52 ,  1052 ,  2052 : Support projection 
               52 A,  1052 ,  2052 : Distal end 
               70 ,  1070 ,  2070 : Joint 
               110 : Second power storage component 
               1051 : Spherical recess