Patent Publication Number: US-11024914-B2

Title: Assembled battery

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to and the benefit of Japanese Patent Application No. 2016-008149 filed Jan. 19, 2016, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an assembled battery. 
     BACKGROUND 
     An assembled battery in which a plurality of batteries is housed in a member such as a case is known. For example, patent literature (PTL) 1 discloses an assembled battery formed by disposing a plurality of lithium-ion cells in a frame member. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP2014-504440A 
     SUMMARY 
     Technical Problem 
     The assembled battery disclosed in PTL 1, however, is manufactured by first assembling a battery module group and then attaching other constituent elements to a terminal cover  800  on the surface of the battery module group. Therefore, the battery module group and the other constituent elements cannot be assembled in parallel, lengthening the takt time for assembly. 
     In light of these considerations, the present disclosure aims to provide an assembled battery that can improve productivity by shortening the takt time for assembly. 
     Solution to Problem 
     To resolve the aforementioned problem, an assembled battery according to a first aspect includes a battery module group including one or more battery cells and a cell holder configured to hold the one or more battery cells, and an auxiliary module group including a plurality of components and a pedestal on which the plurality of components is arranged. The battery module group and the auxiliary module group are attached together by the pedestal being fastened to the cell holder with bus bars. 
     In an assembled battery according to a second aspect, the battery module group and the auxiliary module group are preferably further attached together by an engaging claw of the pedestal engaging with an engaging hole of the cell holder. 
     In an assembled battery according to a third aspect, the pedestal is preferably fastened to the cell holder by connecting a bus bar attached to the pedestal to a bus bar attached to the cell holder. 
     In an assembled battery according to a forth aspect, the pedestal preferably further includes a support along the bus bar attached to the pedestal. 
     In an assembled battery according to a fifth aspect, bus bars fastening the pedestal to the cell holder are preferably attached at any opposing corners of the pedestal, and the pedestal and the cell holder are preferably further attached by bolts at different opposing corners from the any opposing corners. 
     Advantageous Effect 
     The assembled battery according to the first aspect achieves robust attachment without increasing the number of components. 
     The assembled battery according to the second aspect achieves more robust attachment without increasing the number of components. 
     The assembled battery according to the third aspect can reduce an increase in the number of components. 
     The assembled battery according to the forth aspect can prevent attachment between the auxiliary pedestal and the cell holder from weakening due to rotation of the bus bars. Furthermore, screwing of the bus bars is not blocked by rotation of the bus bars. 
     The assembled battery according to the fifth aspect allows attachment of the pedestal and the cell holder at four corners, making the attachment more robust. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is an external perspective view illustrating an assembled battery according to an embodiment of the present disclosure; 
         FIG. 2  is a functional block diagram illustrating an overview of a power supply system that includes the assembled battery illustrated in  FIG. 1 ; 
         FIG. 3  is an external perspective view illustrating the assembled battery in  FIG. 1  with the lower case and cell holder in a transparent state; 
         FIG. 4  is an exploded perspective view of the assembled battery in  FIG. 1 ; 
         FIG. 5  is an external perspective view of the lower case in  FIG. 1 ; 
         FIG. 6  is a top view of the lower case in  FIG. 5 ; 
         FIG. 7A  and  FIG. 7B  are external perspective views of the cell holder in  FIG. 1 ; 
         FIG. 8  is an external perspective view illustrating the cell holder in  FIGS. 7A and 7B  attached to the lower case in  FIG. 5 ; 
         FIG. 9  is an expanded external perspective view of an inter-cell bus bar attached to the cell holder; 
         FIG. 10  schematically illustrates the adhesion positions of the battery cell to the lower case and the cell holder in the assembled battery of  FIG. 1 ; 
         FIG. 11A  and  FIG. 11B  schematically illustrate the state before and after engagement between an engaging claw of the cell holder and an engaging hole of the lower case; 
         FIG. 12  is an external perspective view of the auxiliary pedestal in  FIG. 1 ; 
         FIG. 13A  and  FIG. 13B  are side views of the auxiliary pedestal in  FIG. 1  from one side; 
         FIG. 14  is an external perspective view of the auxiliary pedestal illustrating a state in which the components and bus bars are attached; 
         FIG. 15  is a top view of the auxiliary pedestal illustrating a state in which the components and bus bars are fixed with nuts; 
         FIG. 16  illustrates assembly of the entire assembled battery; and 
         FIG. 17  illustrates attachment of a battery module group and an auxiliary module group. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are described below in detail with reference to the drawings. 
       FIG. 1  is an external perspective view of an assembled battery according to an embodiment of the present disclosure, illustrating a state in which the upper case of the assembled battery is removed. In  FIG. 1 , however, the depiction of each component is partially simplified. Details of each component are provided in  FIG. 5  through  FIG. 15 . The assembled battery  100  includes a lower case  110  housing battery cells, a cell holder  120  holding the battery cells housed in the lower case  110  at the side where an upper case is attached (top side), an auxiliary pedestal  200  attached to the top side of the cell holder  120 , various components attached to the auxiliary pedestal  200 , and an upper case, not illustrated in  FIG. 1 , for protecting the components. The auxiliary pedestal  200  corresponds to the pedestal of the present disclosure. 
     In the present embodiment, the assembled battery  100  includes a metal oxide semiconductor field effect transistor (MOSFET)  210 , a relay  220 , a current sensor  230 , and a fusible link  240  as the components attached to the auxiliary pedestal  200 . The assembled battery  100  includes three terminals that project to the outside of the upper case when the upper case is attached: an SSG terminal  250 , a LOAD terminal  260 , and a GND terminal  270 . 
     In the present embodiment, the assembled battery  100  is described as being mounted and used in a vehicle, such as a vehicle that includes an internal combustion engine or a hybrid vehicle that can run on power of both an internal combustion engine and an electric motor, but the uses of the assembled battery  100  are not limited to vehicles. 
       FIG. 2  is a functional block diagram illustrating an overview of a power supply system that includes the assembled battery  100  in  FIG. 1 . A power supply system  400  includes the assembled battery  100 , an alternator  410 , a starter  420 , a second secondary battery  430 , a load  440 , a switch  450 , and a controller  460 . The assembled battery  100  includes a first secondary battery  130  housed in the lower case  110 . The first secondary battery  130 , the alternator  410 , the starter  420 , the second secondary battery  430 , and the load  440  are connected in parallel. 
     The assembled battery  100  includes the MOSFET  210 , the relay  220 , the current sensor  230 , the fusible link  240 , the first secondary battery  130 , and a battery controller (LBC)  140 . The relay  220 , the current sensor  230 , the fusible link  240 , and the first secondary battery  130  are connected in series in this order. The MOSFET  210  is connected in series with the second secondary battery  430  and the load  440 . 
     The SSG terminal  250  is connected to the alternator  410  and the LOAD terminal  260  is connected to the load  440  in the assembled battery  100 . The GND terminal  270  is used for grounding. 
     The relay  220  functions as a switch that connects the first secondary battery  130  in parallel with constituent elements outside of the assembled battery  100  in the power supply system  400  or disconnects the first secondary battery  130 . 
     The current sensor  230  has an appropriate structure and uses an appropriate method to measure current flowing in a circuit that includes the first secondary battery  130 . 
     The fusible link  240  is configured by a fuse body, a housing made of insulating resin for holding the fuse body, and a cover made of insulating resin for covering the housing. The fusible link  240  fuses when overcurrent occurs. 
     The first secondary battery  130  is constituted by an assembly of battery cells  150  housed in the lower case  110 , as illustrated in  FIG. 3 , which illustrates the lower case  110  and the cell holder  120  in a transparent state. Each battery cell  150  in the first secondary battery  130  is, for example, a secondary battery such as a lithium-ion battery or a nickel-hydrogen battery. The first secondary battery  130  is connected to the fusible link  240  at the positive electrode side and is grounded via the GND terminal  270  at the negative electrode side. 
     The MOSFET  210  functions as a switch that connects the second secondary battery  430  and the load  440  in parallel with other constituent elements in the power supply system  400  or disconnects the second secondary battery  430  and the load  440 . 
     The LBC  140  is connected to the first secondary battery  130  and estimates the state of the first secondary battery  130 . For example, the LBC  140  estimates the state of charge (SOC) or the like of the first secondary battery  130 . 
     The alternator  410  is an electrical generator and is connected mechanically to the vehicle&#39;s engine. The alternator  410  generates electricity by being driven by the engine. The output voltage of the electric power that the alternator  410  generates by being driven by the engine is adjusted by a regulator, and the electric power can be supplied to the first secondary battery  130  provided in the assembled battery  100 , the second secondary battery  430 , and the load  440 . The alternator  410  can also generate electricity by regeneration, for example when the vehicle slows down. The electric power that the alternator  410  generates by regeneration is used to charge the first secondary battery  130  and the second secondary battery  430 . 
     The starter  420  is, for example, configured to include a cell motor, receives a power supply from at least one of the first secondary battery  130  and the second secondary battery  430 , and starts the engine of the vehicle. 
     The second secondary battery  430  is constituted by a lead storage battery, for example, and supplies electric power to the load  440 . 
     The load  440  includes, for example, the audio, air-conditioner, navigation system, and the like provided in the vehicle. The load  440  operates by consuming the supplied electric power. The load  440  operates by receiving the electric power supplied from the first secondary battery  130  while driving of the engine is suspended and operates by receiving the electric power supplied from the alternator  410  and the second secondary battery  430  during driving of the engine. 
     The switch  450  is connected in series to the starter  420 . The switch  450  connects the starter  420  in parallel with other constituent elements or disconnects the starter  420 . 
     The controller  460  controls overall operations of the power supply system  400 . The controller  460  is, for example, constituted by the electric control unit or engine control unit (ECU) of the vehicle. The controller  460  controls operations of the switch  450 , the MOSFET  210 , and the relay  220 , supplies power with the alternator  410 , the first secondary battery  130 , and the second secondary battery  430 , and charges the first secondary battery  130  and the second secondary battery  430 . 
     Next, the detailed structure of the assembled battery  100  is described with reference to  FIG. 4  through  FIG. 17 .  FIG. 4  is an exploded perspective view of the assembled battery in  FIG. 1 . In  FIG. 4 , however, the depiction of each component is partially simplified, as in  FIG. 1 .  FIG. 5  is an external perspective view of the lower case  110 , and  FIG. 6  is a top view of the lower case  110 .  FIG. 7A  and  FIG. 7B  are external perspective views of the cell holder  120 .  FIG. 7A  is an external perspective view of the cell holder  120  from the top side, and  FIG. 7B  is an external perspective view of the cell holder  120  from the opposite side from the top side (bottom side).  FIG. 8  is an external perspective view illustrating the cell holder  120  attached to the lower case  110 .  FIG. 9  is an expanded external perspective view of an inter-cell bus bar  160  attached to the cell holder  120 .  FIG. 10  schematically illustrates the adhesion positions of the battery cell  150  to the lower case  110  and the cell holder  120  in the assembled battery  100 .  FIG. 11A  and  FIG. 11B  schematically illustrate the state before and after engagement between an engaging claw  128  of the cell holder  120  and an engaging hole  115  of the lower case  110 .  FIG. 12  is an external perspective view of the auxiliary pedestal  200 , and  FIG. 13A  and  FIG. 13B  are side views of the auxiliary pedestal  200  from one side.  FIG. 13A  is a side view of only the auxiliary pedestal  200 , and  FIG. 13B  is a side view of a state in which components such as the relay  220  are mounted on the auxiliary pedestal  200 .  FIG. 14  is an external perspective view of the auxiliary pedestal  200  illustrating a state in which the components and bus bars are attached.  FIG. 15  is a top view of the auxiliary pedestal  200  illustrating a state in which the components and bus bars are fixed with nuts  290 . As illustrated in  FIG. 15 , the auxiliary pedestal  200  has corners C 1  through C 4 .  FIG. 16  illustrates assembly of the entire assembled battery, and  FIG. 17  illustrates attachment of a battery module group B and an auxiliary module group S. 
     The assembled battery  100  according to the present embodiment is assembled by assembling the battery module group B and the auxiliary module group S and subsequently attaching the battery module group B and auxiliary module group S together and fixing the upper case. The assembly and the attachment are performed by an assembly apparatus. The battery module group B and the auxiliary module group S are assembled separately and therefore can be assembled in parallel, allowing the assembly takt time to be shortened and improving productivity of the assembled battery  100 . Furthermore, the battery module group B and the auxiliary module group S are attached together after being assembled separately. Hence, as compared to when the entire assembled battery  100  is assembled in sequence, components are discarded less frequently due to backtracking when problems occur during attachment. 
     The battery module group B is constituted by attaching together the battery cells  150 , the lower case  110  housing the battery cells  150 , the cell holder  120  holding the battery cells  150 , the inter-cell bus bars  160 , a total plus terminal bus bar  164 , a total minus terminal bus bar  165 , and the LBC  140 . 
     In the present embodiment, the battery cells  150  provided in the assembled battery  100  have a substantially cuboid shape. The assembled battery  100  of the present embodiment houses five battery cells  150 , but the total number of battery cells  150  that the assembled battery  100  can house is not limited to five. The total number of battery cells  150  that the assembled battery  100  can house is appropriately determined in accordance with factors such as the maximum output of the battery cells  150  and the electric power consumed by driven devices of the vehicle or the like. 
     As illustrated in  FIG. 5 , the lower case  110  is a case that includes a space  110   a  capable of housing the battery cells  150  from the top side. In other words, the lower case  110  has a bottom  111 , four sides  112   a ,  112   b ,  112   c , and  112   d , and an opening  113  on the opposite side from the bottom  111  (i.e. on the top side). In the lower case  110 , the sides  112   a  and  112   c  face each other, and the sides  112   b  and  112   d  face each other. When not differentiating between the four sides  112   a ,  112   b ,  112   c , and  112   d , these sides are collectively referred to below as the sides  112 . The height of the sides  112  is less than the height of the battery cells  150  housed in the lower case  110 . 
     The sides  112   b  and  112   d  each include an attachment mechanism  114  for attaching the assembled battery  100  to a vehicle on the outside of the lower case  110  (i.e. on the opposite side from the space  110   a ). The shape of the attachment mechanism  114  and the position on the sides  112   b  and  112   d  are determined appropriately in accordance with the method of attachment to the vehicle. 
     The sides  112  have engaging holes  115  for engagement with the cell holder  120  on the opening  113  side. In the present embodiment, each side  112  has three engaging holes  115 , located at the center and near the edges of the opening  113 . 
     The bottom  111  includes guides  116 , on the inside of the lower case  110  (i.e. the space  110   a  side), to indicate the position of the battery cells  150  to be housed and to prevent misalignment of the housed battery cells  150 . The guides  116  also have the function of maintaining a space between battery cells  150 . An insulating sheet, for example, may be inserted in the space between battery cells  150  formed by the guides  116 . 
     The height of the guides  116  is less than the height of the sides  112 . In the present embodiment, four guides  116  are provided parallel to the sides  112   b  and  112   d  at equal intervals. In other words, the lower case  110  in the present embodiment houses five battery cells  150  disposed to be stacked from the side  112   b  to the side  112   d  along five regions of the bottom  111  partitioned by the guides  116 . 
     In general, when manufacturing the lower case  110 , dimensional error is less likely to occur in the sides  112   a  and  112   c , which do not include the attachment mechanism  114 , than in the sides  112   b  and  112   d , which do include the attachment mechanism  114 . Therefore, by disposing the battery cells  150  to be stacked along the direction of the sides  112   a  and  112   c , as in the present embodiment, the battery cells  150  housed in the lower case  110  are less likely to shift within the lower case  110  in the stacking direction. 
     The position, size, and the like of the guides  116  are appropriately determined in accordance with the shape, number, and the like of the battery cells  150  housed by the lower case  110 . 
     The battery cell  150  includes a positive electrode terminal  152  and a negative electrode terminal  153  on one substantially cuboid cap surface  151 . The cap surface  151  is rectangular, with long sides and short sides, and the positive electrode terminal  152  and the negative electrode terminal  153  are provided near the edges in the direction of the long sides of the cap surface  151 . A safety valve  154  is provided at the center of the cap surface  151 . The safety valve  154  opens to discharge gas to the outside when, due to deterioration over time, thermal runaway, or the like, gas is produced inside the battery cell  150  and the inside of the battery cell  150  reaches a predetermined pressure or greater. The battery cell  150  is housed in the lower case  110  so that the cap surface  151  projects from the opening  113 , i.e. to become the top side. As illustrated in  FIG. 4 , the battery cells  150  are housed within the lower case  110  so that the positive electrode terminal  152  and the negative electrode terminal  153  of adjacent battery cells  150  are arranged in opposite directions in the lower case  110 . 
     The cell holder  120  is attached at the cap surface  151  side of the battery cell  150 , i.e. at the opening  113  side of the lower case  110 . 
     The cell holder  120  includes an outer frame  121  and a holding lid  122  on the inside of the outer frame  121 . The outer frame  121  is substantially rectangular in a top view and has a predetermined height. The holding lid  122  holds the battery cells  150  from the top side when the cell holder  120  is engaged with the lower case  110 . The holding lid  122  holds the cap surface  151  of the battery cells  150 , housed in the lower case  110 , from the top side. 
     As illustrated in  FIG. 8 , the outer frame  121  has four sides  121   a ,  121   b ,  121   c , and  121   d . The four sides  121   a ,  121   b ,  121   c , and  121   d  are disposed at positions corresponding to the four sides  112   a ,  112   b ,  112   c , and  112   d  of the lower case  110  when the outer frame  121  and the lower case  110  are engaged. 
     The outer frame  121  includes screw hole forming portions  123 , at the edges of the sides  121   b  and  121   d , that have a screw hole  123   a  for fixing the auxiliary pedestal  200  to the cell holder  120  by screwing. The screw hole forming portions  123  are formed to project outward from the sides  121   b  and  121   d . The screw hole  123   a  is formed in the screw hole forming portion  123  to allow insertion of a screw from the top side. 
     The outer frame  121  has screw holes  123   b , at the top side of the sides  121   b  and  121   d , for screwing bus bars attached to the auxiliary pedestal  200  (i.e. the below-described total plus copper bus bar  285  and total minus copper bus bar  286 ) to the cell holder  120 . The screw holes  123   b  are preferably provided near the opening  124   a  (illustrated in  FIG. 7A ) where the below-described total plus terminal bus bar  164  and total minus terminal bus bar  165  are attached. 
     The holding lid  122  has openings  124   a  at positions corresponding to the positive electrode terminal  152  and negative electrode terminal  153  of the battery cells  150  when the cell holder  120  and the lower case  110  are engaged. In other words, as illustrated in  FIG. 8 , the positive electrode terminal  152  and negative electrode terminal  153  of the battery cells  150  are exposed to the top side of the holding lid  122  through the openings  124   a  when the cell holder  120  and the lower case  110  are engaged. 
     The holding lid  122  has openings  124   b  at positions corresponding to the safety valves  154  of the battery cells  150  when the cell holder  120  and the lower case  110  are engaged. In other words, as illustrated in  FIG. 8 , gas discharged from the safety valves  154  is discharged outside the battery cells  150  through the openings  124   b  when the cell holder  120  and the lower case  110  are engaged. 
     Adjacent terminals among the positive electrode terminals  152  and negative electrode terminals  153 , which are exposed through the openings  124   a  and arranged in a line, electrically connect through inter-cell bus bars  160 , except for a positive electrode terminal  152  that connects to the fusible link  240  and a negative electrode terminal  153  that connects to the GND terminal  270 . The inter-cell bus bar  160  is, for example, made of a conductive metal such as aluminum. The inter-cell bus bar  160  has a convex portion  161  for avoiding interference with a frame portion  122   a  of the holding lid  122  between openings  124   a  when the inter-cell bus bar  160  is attached to the cell holder  120  and connected to the positive electrode terminal  152  and the negative electrode terminal  153 . In other words, in a side view, the inter-cell bus bar  160  has two terminal connectors  162  connecting to the positive electrode terminal  152  and the negative electrode terminal  153  and has the convex portion  161  connecting the two terminal connectors  162  and projecting from the terminal connectors  162  toward the top side. 
     The terminal connectors  162  have openings for welding  162   a  at the center, for example as illustrated in  FIG. 9 . The inter-cell bus bars  160  and the below-described total plus terminal bus bar  164  and total minus terminal bus bar  165  are connected to the terminals of the battery cells  150  by bead welding at the periphery of the openings for welding  162   a.    
     Each terminal connector  162  has a voltage sensor attachment terminal  163  that projects towards the opening  124   b  when the terminal connector  162  is attached to the cell holder  120 . Each voltage sensor attachment terminal  163  has a screw hole  163   a . In the inter-cell bus bar  160 , each voltage sensor attachment terminal  163  is formed to be disposed on the below-described screw hole forming portion  126  when the terminal connector  162  of the inter-cell bus bar  160  is connected to the positive electrode terminal  152  or the negative electrode terminal  153 . The screw hole  163   a  overlaps with a screw hole  126   a  formed in the screw hole forming portion  126  when the voltage sensor attachment terminal  163  is disposed on the screw hole forming portion  126 , and by screwing of the LBC  140 , the screw hole  126   a  and the screw hole  163   a  are screwed together. The voltage sensor attachment terminal  163  is connected to a voltage sensor and used to detect the voltage between terminals. 
     The total plus terminal bus bar  164  connects to the positive electrode terminal  152  that connects to the fusible link  240 , and the total minus terminal bus bar  165  connects to the negative electrode terminal  153  that connects to the GND terminal  270 . The total plus terminal bus bar  164  and total minus terminal bus bar  165  are, for example, made of a conductive metal such as aluminum. The total plus terminal bus bar  164  and total minus terminal bus bar  165  each have one terminal connector  162  and an external connector  166  for connecting respectively to the total plus copper bus bar  285  and total minus copper bus bar  286  provided in the auxiliary pedestal  200 . The external connector  166  has a convex shape, projecting further towards the top side than the terminal connector  162 , so as to clamp the inner surface and outer surface of the outer frame  121 . In particular, as illustrated in  FIG. 16 , the external connector  166  is attached along a bus bar support  123   c  formed to extend from the inner surface to the outer surface of the outer frame  121 . The external connector  166  has screw holes  166   a  at positions corresponding to the screw holes  123   b  when the external connector  166  is attached to the outer frame  121 . The terminal connector  162  of the total plus terminal bus bar  164  and the total minus terminal bus bar  165  also has a voltage sensor attachment terminal  163  that projects towards the opening  124   b  when the terminal connector  162  is attached to the cell holder  120 . 
     The holding lid  122  includes beads  125  between bus bars that are attached to the cell holder  120 , i.e. between inter-cell bus bars  160  and between an inter-cell bus bar  160  and the total plus terminal bus bar  164  or the total minus terminal bus bar  165 , to prevent electrical connection between the bus bars and to position the bus bars. The beads  125  project toward the top side of the holding lid  122 . 
     The holding lid  122  also includes screw hole forming portions  126  for fixing the LBC  140  to the top side. The screw hole forming portions  126  are formed between the openings  124   a  and the openings  124   b  on the top side of the holding lid  122 . In other words, in the present embodiment, the holding lid  122  includes ten screw hole forming portions  126 . Each screw hole forming portion  126  is substantially cylindrical, and a screw hole  126   a  is provided at the center thereof. The LBC  140  is mounted on the top side of the cell holder  120  and is screwed to the cell holder  120  from the top side using the screw holes  126   a  formed in the screw hole forming portions  126 . 
     The holding lid  122  includes ribs  127 , on the bottom side, to prevent misalignment of the battery cells  150  housed in the lower case  110 . Four ribs  127  are provided at equal intervals in parallel to the sides  121   b  and  121   d . In other words, the ribs  127  of the holding lid  122  are provided in a direction and at positions corresponding to the guides  116  of the lower case  110  when the cell holder  120  and the lower case  110  are engaged. 
     The outer frame  121  has an engaging insertion portion  121   e  with a predetermined height around the entire periphery. The engaging insertion portion  121   e  is thinner than other locations of the outer frame  121 . Therefore, at the outer surface of the outer frame  121 , the engaging insertion portion  121   e  is recessed more than other locations of the outer frame  121 . As illustrated in  FIG. 11B , the engaging insertion portion  121   e  is inserted inside the lower case  110  at the opening  113  side of the lower case  110  when the cell holder  120  is engaged with the lower case  110 . 
     On each of the sides  121   a ,  121   b ,  121   c , and  121   d , the engaging insertion portion  121   e  includes three engaging claws  128  located at the center and near the edges. The engaging claws  128  are provided at positions corresponding to the engaging holes  115  of the lower case  110 . To engage the cell holder  120  with the lower case  110 , the engaging claws  128  of the cell holder  120  are fit into and engaged with the engaging holes  115  of the lower case  110 , thereby engaging the cell holder  120  with the lower case  110 . The position and number of engaging holes  115  and engaging claws  128  are not limited to the example illustrated in the present embodiment and may be determined as appropriate. 
     The outer frame  121  includes engaging holes  129   a  on the top side of the sides  121   a  and  121   c  near the screw holes  123   b . The engaging holes  129   a  are provided to project to the outside from the outer frame  121  and are substantially rectangular holes in a top view. The engaging holes  129   a  are used when the cell holder  120  and the auxiliary pedestal  200  are attached. 
     The outer frame  121  includes an engaging hole  129   b  at the top side near the center of each side  121   a ,  121   b ,  121   c , and  121   d . The engaging holes  129   b  are provided to project to the outside from the outer frame  121  and are substantially rectangular holes in a top view. The engaging holes  129   b  are used when attaching the cell holder  120  and the upper case. The engaging holes  129   b  need not be provided near the center of the sides  121   a ,  121   b ,  121   c , and  121   d  and may be provided at any position that allows engagement with the below-described upper case. 
     Here, assembly of the battery module group B is described. First, adhesive is applied to the battery cells  150 . Any adhesive that can adhere the battery cells  150  to the lower case  110  and the cell holder  120  may be used, such as an epoxy adhesive. Since it suffices for the position of the battery cells  150  to be fixed in the lower case  110  when the cell holder  120  is engaged with the lower case  110 , the adhesive need not be applied on the entire battery cell  150  and may instead be applied on a portion of the battery cell  150 . For example, the adhesive may be applied to the battery cell  150  on the surface that comes into contact with the bottom  111  when the battery cell  150  is inserted in the lower case  110  (i.e. the opposite side from the cap surface  151 ) and the surface that comes into contact with the holding lid  122  when the battery cell  150  is held by the cell holder  120  from the top side (i.e. the cap surface  151 ). In particular, the cap surface  151  includes the positive electrode terminal  152 , the negative electrode terminal  153 , and the safety valve  154 . Therefore, to avoid application of adhesive on the positive electrode terminal  152 , the negative electrode terminal  153 , and the safety valve  154 , the adhesive may, for example, be applied only at the periphery in the longitudinal direction of the cap surface  151 . 
       FIG. 10  schematically illustrates the adhesion positions, in the battery cell  150 , when adhesive is applied to the surface that comes into contact with the bottom  111  when the battery cell  150  is inserted in the lower case  110  and the surface that comes into contact with the holding lid  122  when the battery cell  150  is held by the cell holder  120  from the top side (i.e. the cap surface  151 ).  FIG. 10  is a cross-section along the A-A line in  FIG. 8 . Among the five stacked battery cells  150 ,  FIG. 10  only particularly illustrates the battery cell  150  at the center and the surrounding area. In  FIG. 10 , the region to which adhesive is applied is indicated with shading. In this case, as illustrated in  FIG. 10 , the battery cell  150  is adhered to the cell holder  120  in the area surrounding the intersection between the holding lid  122  and the ribs  127  and is adhered to the lower case  110  at the bottom  111 . 
     The material applied between the battery cells  150  and the bottom  111  of the lower case  110  is not limited to adhesive. Another filler may be applied between the battery cells  150  and the bottom  111 . The filler preferably has elasticity in particular. By applying filler with elasticity between the battery cells  150  and the bottom  111 , vibration occurring during running of the vehicle provided with the assembled battery  100  is absorbed by the filler. Therefore, vibration is not easily transmitted to the battery cells  150 . 
     Next, with the cell holder  120  turned upside down, the cap surface  151  of the battery cells  150  is pointed downwards, and the battery cells  150  are inserted in accordance with the ribs  127  at the bottom side of the holding lid  122  of the cell holder  120 . With the lower case  110  upside down, the lower case  110  is then engaged with the cell holder  120  so as to cover the cell holder  120  in which the battery cells  150  were inserted. As illustrated in  FIG. 11A  and  FIG. 11B , the engaging claws  128  of the cell holder  120  are engaged with the engaging holes  115  of the lower case  110 .  FIG. 8  illustrates an example of the cell holder  120  and the lower case  110  in an engaged state. 
     The procedure for adhering the battery cells  150  is not limited to the aforementioned procedure. For example, without turning the lower case  110  and the cell holder  120  upside down, the battery cells  150  may be inserted in the space  110   a  of the lower case  110 , and the cell holder  120  may be engaged with the lower case  110  from above. 
     The inter-cell bus bars  160 , the total plus terminal bus bar  164 , and the total minus terminal bus bar  165  are then attached by bead welding to the terminals of the battery cells  150  exposed through the openings  124   a  of the holding lid  122 , and the LBC  140  is attached to the holding lid  122 , thereby completing assembly of the battery module group B. As described above, the LBC  140  is attached to the holding lid  122  by screwing, for example. 
     Next, the auxiliary module group S of the assembled battery  100  according to the present embodiment is described. The auxiliary module group S is configured by attaching together the auxiliary pedestal  200 , the MOSFET  210 , relay  220 , current sensor  230 , and fusible link  240  disposed on the auxiliary pedestal  200 , and copper bus bars for electrically connecting the components disposed on the auxiliary pedestal  200 . 
     The auxiliary pedestal  200  has four sides  200   a ,  200   b ,  200   c , and  200   d , and a mounting surface  201 . The four sides  200   a ,  200   b ,  200   c , and  200   d  are disposed at positions corresponding to the four sides  112   a ,  112   b ,  112   c , and  112   d  of the lower case  110  (and the four sides  121   a ,  121   b ,  121   c , and  121   d  of the cell holder  120 ) when the auxiliary pedestal  200  is attached to the battery module group B. 
     The current sensor  230  near the side  200   a , the MOSFET  210  near the side  200   b , the relay  220  near the side  200   c , and the fusible link  240  near the side  200   d  are mounted on the mounting surface  201 . As illustrated in  FIG. 12 , the mounting surface  201  is uneven in accordance with the positions at which the MOSFET  210 , relay  220 , current sensor  230 , and fusible link  240  are mounted. By being uneven, the mounting surface  201  is more rigid than a flat mounting surface. 
     In the present embodiment, the mounting surface  201  is formed to have an unevenness such that a region  201   c  where the relay  220  is mounted on the mounting surface  201  is at a higher position when the assembled battery  100  is assembled than a region  201   a  where the current sensor  230  is mounted, a region  201   b  where the MOSFET  210  is mounted, and a region  201   d  where the fusible link  240  is mounted, as illustrated in  FIG. 12 . The unevenness of the mounting surface  201  is such that the region  201   d  where the fusible link  240  is mounted is at a higher position when the assembled battery  100  is assembled than the region  201   a  and the region  201   b . In other words, the unevenness of the mounting surface  201  is such that the region  201   a  where the current sensor  230  is mounted is at a lower position than the region  201   c  and the region  201   d . By the mounting surface  201  having such an unevenness, the fusible link  240  can be disposed at a lower position than the relay  220  on the auxiliary pedestal  200 , and the current sensor  230 , which is thicker than the fusible link  240 , can also be disposed at a lower position than the relay  220 . 
     The current sensor  230 , MOSFET  210 , relay  220 , and fusible link  240  are positioned in the respective regions  201   a ,  201   b ,  201   c , and  201   d  by standing walls formed by the unevenness of the mounting surface  201  or by ribs  202  formed on the mounting surface  201 . 
     In the present embodiment, the region  201   c  is partially surrounded by the ribs  202 , as illustrated in  FIG. 12  and  FIG. 14 , for example. In other words, the relay  220  is positioned by the ribs  202 . The ribs  202  also have a rotation-stopping function when the relay  220  is fixed to the auxiliary pedestal  200  with nuts  290 . The ribs  202  also have an insulating function to prevent contact between the below-described copper bus bars. 
     The MOSFET  210 , relay  220 , and fusible link  240  are positioned by standing walls formed to partially surround the respective regions  201   a ,  201   b , and  201   d . The standing walls on the mounting surface  201  also have a rotation-stopping function when the MOSFET  210 , the relay  220 , and the fusible link  240  are fixed to the auxiliary pedestal  200  with nuts  290 . 
     The auxiliary pedestal  200  includes a plurality of upward-facing studs  203  on the mounting surface  201 . The studs  203  are used to connect the battery cells  150  of the battery module group B, the MOSFET  210 , the relay  220 , the current sensor  230 , and the fusible link  240  electrically to each other. The SSG terminal  250 , the LOAD terminal  260 , and the GND terminal  270  also extend upward from the mounting surface  201  and function as studs. 
     Each stud  203 , the SSG terminal  250 , the LOAD terminal  260 , and the GND terminal  270  are provided at appropriate heights on the uneven mounting surface  201 . For example, the studs  203  are provided at a height corresponding to the terminals of the current sensor  230 , the MOSFET  210 , the relay  220 , and the fusible link  240  respectively mounted in the regions  201   a ,  201   b ,  201   c , and  201   d  on the mounting surface  201 . Each stud  203  has a diameter corresponding in size to an opening for connection provided in the terminals of the current sensor  230 , the MOSFET  210 , the relay  220 , and the fusible link  240 . The current sensor  230 , the MOSFET  210 , the relay  220 , and the fusible link  240  are attached to the auxiliary pedestal  200  by passing the studs  203  through the openings for connection of the terminals from the top side. Providing the studs  203  to face upward in this way facilitates attachment of the components to the auxiliary pedestal  200 , thereby improving the productivity of the auxiliary module and the assembled battery  100 . 
     Furthermore, in the present embodiment, the GND terminal  270  is provided at a lower position than the SSG terminal  250  and the LOAD terminal  260 . Setting the GND terminal  270  to differ in height from the SSG terminal  250  and the LOAD terminal  260  in this way increases the distinguishability of the GND terminal  270 , thereby facilitating prevention of miswiring when mounting the assembled battery  100  in a vehicle. 
     Here, the wiring of components using copper bus bars on the auxiliary pedestal  200  is described. As illustrated in  FIG. 14  and  FIG. 15 , the copper bus bars  280  through  284  have various shapes in accordance with their position so as to follow the unevenness of the mounting surface  201  of the auxiliary pedestal  200 . 
     A terminal  240   b  of the fusible link  240  connects electrically to a terminal  230   a  of the current sensor  230  via the copper bus bar  280 . The other terminal  230   b  of the current sensor  230  connects electrically to a terminal  220   a  of the relay  220  via the copper bus bar  281 . The other terminal  220   b  of the relay  220  connects electrically to a terminal  210   a  of the MOSFET  210  via the copper bus bar  282 . The terminal  220   b  of the relay  220  further connects electrically to the SSG terminal  250  via the copper bus bars  282  and  283 . The other terminal  210   b  of the MOSFET  210  connects electrically to the LOAD terminal  260  via the copper bus bar  284 . 
     The total plus copper bus bar  285  for electrically connecting to the total plus terminal bus bar  164  of the battery module group B connects to a terminal  240   a  of the fusible link  240 . The total minus copper bus bar  286  for electrically connecting to the total minus terminal bus bar  165  of the battery module group B connects to the GND terminal  270 . The total plus copper bus bar  285  and the total minus copper bus bar  286  extend respectively along the bottom side of the sides  200   b  and  200   d , and the tips thereof respectively come in contact with the total plus terminal bus bar  164  and the total minus terminal bus bar  165  when the auxiliary pedestal  200  and the cell holder  120  are attached, thereby ensuring electrical connection. The total plus copper bus bar  285  and the total minus copper bus bar  286  have, at the tips thereof, respective screw holes  285   a  and  286   a  at positions corresponding to the screw holes  123   b  provided on the cell holder  120  when the auxiliary pedestal  200  and the cell holder  120  are attached. 
     The copper bus bars  280  through  284  and the total plus copper bus bar  285  are secured to the auxiliary pedestal  200  along with the MOSFET  210 , relay  220 , current sensor  230 , and fusible link  240  by the nuts  290 , which are screwed onto the studs  203  from the top side. The relay  220  has openings  221  at different positions from the terminal  220   a  and the terminal  220   b  and is also secured to the auxiliary pedestal  200  by the openings  221  being placed onto the studs  203  and the nuts  290  being screwed to the studs  203  from the top side. 
     As described above, the ribs  202  provided on the auxiliary pedestal  200  prevent the copper bus bars from being in contact. Furthermore, dividing walls  222  provided at the terminal  220   a  and the terminal  220   b  of the relay  220  also have an insulating function to prevent contact between the copper bus bars. 
     The auxiliary pedestal  200  includes screw hole forming portions  204 , at the edges of the sides  200   b  and  200   d , that have a screw hole  204   a  for fixing the cell holder  120  and the auxiliary pedestal  200  by screwing. The screw hole  204   a  is provided at a position corresponding to the screw hole  123   a  provided on the cell holder  120  when the cell holder  120  and the auxiliary pedestal  200  are attached. 
     The auxiliary pedestal  200  includes engaging claws  205  on the side  200   a  near the stud  203  to which the total plus copper bus bar  285  is attached and on the side  200   c  near the GND terminal  270  to which the total minus copper bus bar  286  is attached. The engaging claws  205  are provided at positions corresponding to the engaging holes  129   a  when the cell holder  120  and the auxiliary pedestal  200  are attached. The engaging claws  205  extend towards the bottom from the exterior of the sides  200   a  and  200   c , and the tips of the engaging claws  205  are wedge-shaped in a side view. The engaging claws  205  engage with the engaging holes  129   a  by the tips of the engaging claws  205  being fit into the engaging holes  129   a.    
     Here, assembly of the auxiliary module group S is described. During assembly of the auxiliary module group S, the components (i.e. the MOSFET  210 , relay  220 , current sensor  230 , and fusible link  240 ) and the copper bus bars (i.e. the copper bus bars  280  through  284 , the total plus copper bus bar  285 , and the total minus copper bus bar  286 ) are placed onto the studs  203 , the SSG terminal  250 , the LOAD terminal  260 , and the GND terminal  270  of the mounting surface  201  of the auxiliary pedestal  200 . The auxiliary module group S is then assembled by the nuts  290  being screwed onto the studs  203 , the SSG terminal  250 , the LOAD terminal  260 , and the GND terminal  270  from the top side. 
     Next, the upper case is described. As illustrated in  FIG. 16 , the upper case  300  has three openings  310   a ,  310   b , and  310   c  for exposing the SSG terminal  250 , the LOAD terminal  260 , and the GND terminal  270  to the outside from the upper case  300  when the assembled battery  100  is assembled. 
     The upper case  300  also includes engaging claws  320  for engaging with the cell holder  120  at the bottom of the four sides. The engaging claws  320  are provided at positions corresponding to the engaging holes  129   b  when the cell holder  120  and the upper case  300  are attached together. The engaging claws  320  extend towards the bottom from the exterior of the sides, and the tips of the engaging claws  320  are wedge-shaped in a side view. The engaging claws  320  engage with the engaging holes  129   b  by the tips of the engaging claws  320  being fit into the engaging holes  129   b.    
     The upper case  300  includes bus bar protectors  330  for protecting the total plus copper bus bar  285  and the total minus copper bus bar  286  when the cell holder  120  and the upper case  300  are attached together. 
     Next, assembly of the entire assembled battery  100  is described. First, attachment of the battery module group B and the auxiliary module group S is described. The battery module group B and the auxiliary module group S are attached together by attaching the cell holder  120  to the auxiliary pedestal  200 . Bus bars, bolts, and the like are used for this attachment. 
     As illustrated in  FIG. 17 , the cell holder  120  and auxiliary pedestal  200  are attached together by the engaging claws  205  being fit into and engaged with the engagement holes  129   a . The engaging claws  205  are provided on the auxiliary pedestal  200 , and the engagement holes  129   a  are provided on the cell holder  120 , thus achieving robust attachment without increasing the number of components. The cell holder  120  and the auxiliary pedestal  200  are attached together by the auxiliary pedestal  200  being placed on the cell holder  120  and bolts  340  being screwed from outside the sides  200   b  and  200   d  into the screw holes  123   b , illustrated in  FIG. 8 , through the screw hole  285   a  or the screw hole  286   b  and the screw holes  166   a . In other words, as illustrated in  FIG. 17 , the cell holder  120  and auxiliary pedestal  200  are attached together indirectly by the bolts  340  through two bus bars (the total minus copper bus bar  286  and the total minus terminal bus bar  165 ) at the corner C 1  of the auxiliary pedestal  200 . The cell holder  120  and auxiliary pedestal  200  are also attached together indirectly by the bolts  340  through two bus bars (the total plus copper bus bar  285  and the total plus terminal bus bar  164 ) at the corner C 2  opposite the corner C 1 . In other words, the bus bars that fasten the auxiliary pedestal  200  to the cell holder  120  are attached at any opposing corners (C 1  and C 2  in the present embodiment) of the auxiliary pedestal  200 . Since the bus bars for fastening are required to begin with for electrical connection, robust attachment can be achieved without increasing the number of components. At this time, supports  206  provided along the total plus copper bus bar  285  and the total minus copper bus bar  286  have a rotation-stopping function, thus preventing the attachment between the auxiliary pedestal  200  and the cell holder  120  from weakening. 
     Combining attachment by engagement and attachment with the bolts  340  achieves more robust attachment than use of only one form of attachment. 
     Furthermore, the cell holder  120  and the auxiliary pedestal  200  are attached together by the cell holder  120  being placed on the auxiliary pedestal  200  and bolts  350  then being screwed from the top side into the screw holes  123   a  through the screw holes  204   a , provided on the opposing corners C 3  and C 4  of the auxiliary pedestal  200  (different opposing corners C 3  and C 4  from the opposing corners C 1  and C 2 ), as illustrated in  FIG. 17 . In other words, the auxiliary pedestal  200  and the cell holder  120  are attached together at four corners (C 1  through C 4 ), making the attachment more robust. The bolts  350  in the present embodiment are, for example, M6 (6 mm diameter). 
     The battery module group B and the auxiliary module group S of the present embodiment are attached together in the above-described way, thereby fixing the battery module group B and the auxiliary module group S at the four corners of the auxiliary pedestal  200 , which is substantially rectangular in a top view. This structure achieves robust attachment. 
     Next, attachment of the upper case  300  is described. The upper case  300  is engaged with the cell holder  120  by the engaging claws  320  being fit into and engaged with the engagement holes  129   b  of the cell holder  120 . By the upper case  300  thus being engaged with the cell holder  120 , assembly of the entire assembled battery  100  is complete. 
     In this way, the cell holder  120  and the auxiliary pedestal  200  are first assembled and then attached together in the manufacturing method of the assembled battery  100  according to an embodiment of the present disclosure. The battery module group B and the auxiliary module group S can be assembled in parallel, allowing the assembly takt time to be shortened and improving productivity of the assembled battery  100 . Furthermore, as compared to when the entire assembled battery  100  is assembled in sequence, components are discarded less frequently due to backtracking when problems occur during attachment. 
     In the assembled battery  100  according to an embodiment of the present disclosure, the battery module group B and the auxiliary module group S are attached together by the auxiliary pedestal  200  being fastened to the cell holder  120  by bus bars (total plus copper bus bar  285 , total plus terminal bus bar  164 , total minus copper bus bar  286 , and total minus terminal bus bar  165 ). Since these bus bars are required to begin with for electrical connection between the battery module group B and the auxiliary module group S, robust attachment can be achieved without increasing the number of components. 
     The assembled battery  100  according to an embodiment of the present disclosure achieves attachment by the engaging claws  205  of the auxiliary pedestal  200  engaging with the engaging holes  129   a  of the cell holder  120 . The engaging claws  205  are provided on the auxiliary pedestal  200 , and the engagement holes  129   a  are provided on the cell holder  120 , thus achieving robust attachment without further increasing the number of components. 
     In the assembled battery  100  according to an embodiment of the present disclosure, bus bars are fastened by connecting the bus bars attached to the auxiliary pedestal  200  (total plus copper bus bar  285  and total minus copper bus bar  286 ) and the bus bars attached to the cell holder  120  (total plus terminal bus bar  164  and total minus terminal bus bar  165 ). In other words, the bus bars for electrically connecting the auxiliary pedestal  200  and the cell holder  120  are directly connected, allowing an increase in the number of components to be reduced. 
     In the assembled battery  100  according to an embodiment of the present disclosure, the auxiliary pedestal  200  further includes the supports  206  along the bus bars attached to the auxiliary pedestal  200  (total plus copper bus bar  285  and total minus copper bus bar  286 ). Attachment between the auxiliary pedestal  200  and the cell holder  120  can therefore be prevented from weakening due to rotation of the bus bars. Furthermore, screwing of the bus bars is not blocked by rotation of the bus bars. 
     In the assembled battery  100  according to an embodiment of the present disclosure, the bus bars that fasten the auxiliary pedestal  200  to the cell holder  120  (total plus copper bus bar  285 , total plus terminal bus bar  164 , total minus copper bus bar  286 , and total minus terminal bus bar  165 ) are attached at any opposing corners (C 1  and C 2 ) of the auxiliary pedestal  200 . The auxiliary pedestal  200  and cell holder  120  are moreover attached together by bolts  350  at different opposing corners (C 3  and C 4 ) from the above opposing corners. In other words, the auxiliary pedestal  200  and the cell holder  120  can be attached together at four corners (C 1  through C 4 ), making the attachment more robust. 
     REFERENCE SIGNS LIST 
     B Battery module group 
     S Auxiliary module group 
       100  Assembled battery 
       110  Lower case 
       110   a  Space 
       111  Bottom 
       112 ,  112   a ,  112   b ,  112   c ,  112   d ,  121   a ,  121   b ,  121   c ,  121   d ,  200   a ,  200   b ,  200   c ,  200   d  Side 
       113 ,  124   a ,  124   b ,  221 ,  310   a ,  310   b ,  310   c  Opening 
       114  Attachment mechanism 
       115 ,  129   a ,  129   b  Engaging hole 
       116  Guide 
       120  Cell holder 
       121  Outer frame 
       121   e  Engaging insertion portion 
       122  Holding lid 
       122   a  Frame portion 
       123 ,  126 ,  204  Screw hole forming portion 
       123   a ,  123   b ,  126   a ,  163   a ,  166   a ,  204   a ,  285   a ,  286   a  Screw hole 
       123   c  Bus bar support 
       125  Bead 
       127 ,  202  Rib 
       128 ,  205 ,  320  Engaging claw 
       130  First secondary battery 
       140  LBC (battery controller) 
       150  Battery cell 
       151  Cap surface 
       152 ,  210   a ,  220   a ,  230   a ,  240   a  Terminal 
       153 ,  210   b ,  220   b ,  230   b ,  240   b  Terminal 
       154  Safety valve 
       160  Inter-cell bus bar 
       161  Convex portion 
       162  Terminal connector 
       162   a  Opening for welding 
       163  Voltage sensor attachment terminal 
       164  Total plus terminal bus bar 
       165  Total minus terminal bus bar 
       166  External connector 
       200  Auxiliary pedestal 
       201  Mounting surface 
       201   a ,  201   b ,  201   c ,  201   d  Region 
       203  Stud 
       206  Support 
       210  MOSFET 
       220  Relay 
       222  Dividing wall 
       230  Current sensor 
       240  Fusible link 
       250  SSG terminal 
       260  LOAD terminal 
       270  GND terminal 
       280 ,  281 ,  282 ,  283 ,  284  Copper bus bar 
       285  Total plus copper bus bar 
       286  Total minus copper bus bar 
       290  Nut 
       300  Upper case 
       330  Bus bar protector 
       340 ,  350  Bolt 
       400  Power supply system 
       410  Alternator 
       420  Starter 
       430  Second secondary battery 
       440  Load 
       450  Switch 
       460  Controller 
     C 1 , C 2 , C 3 , C 4  Corner