Patent Publication Number: US-2022214400-A1

Title: Support plate and voltage detection line module

Description:
TECHNICAL FIELD 
     The present invention relates to a support plate and a voltage detection line module. 
     BACKGROUND ART 
     For example, as a power source for a vehicle or the like that requires a high output voltage, there has been known a battery module formed by electrically connecting a plurality of batteries to each other. In the battery module, neighboring batteries are electrically connected with each other via a bus bar. Additionally, for example, as disclosed in PTL 1, a voltage detection line is attached to each bus bar, and the voltage between the batteries is detected. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: Unexamined Japanese Patent Publication No. 2017-27831 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problem 
     In order to simplify the manufacturing process of a battery module, there is a demand for automating connection of a voltage detection line to a bus bar. In order to achieve the automation, it is effective to employ welding for the connection between the voltage detection line and the bus bar. When the voltage detection line and the bus bar are welded, it is required to accurately position the voltage detection line with respect to the bus bar. However, in the conventional battery module, the positioning accuracy of the voltage detection line is not sufficiently high, and it is sometimes necessary to manually adjust the position of the voltage detection line by the operator. 
     The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique that can enhance positioning accuracy of a voltage detection line. 
     Solution to Problem 
     One aspect of the present invention is a support plate. The support plate is a support plate that supports a voltage detection line for detecting a voltage of a battery, in which: the voltage detection line includes a conductive wire, and a tab terminal that electrically connects a bus bar electrically connected to an output terminal of the battery and the conductive wire; the support plate includes a base plate on which the voltage detection line is placed and a position restricting structure of the tab terminal; and the position restricting structure includes a receiving surface part against which the tab terminal abuts, and a biasing part that pushes the tab terminal toward the receiving surface part. 
     Another aspect of the present invention is a voltage detection line module. The voltage detection line module includes a voltage detection line and the support plate of the above aspect. 
     Note that any combinations of the above-described constituent elements, and configurations that are obtained by expressing the present invention in the form of method, apparatus, system and the like are also effective as an aspect of the present invention. 
     Advantageous Effect of Invention 
     According to the present invention, positioning accuracy of a voltage detection line can be enhanced. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view of a battery module having a support plate according to an exemplary embodiment. 
         FIG. 2  is a plan view of the battery module. 
         FIG. 3  is a perspective view of a region including a tab terminal in a voltage detection line module according to the exemplary embodiment. 
         FIG. 4  is a perspective view schematically illustrating a region including the tab terminal in the voltage detection line module. 
         FIG. 5  is a cross-sectional view schematically illustrating a region including the tab terminal in the voltage detection line module. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Hereinafter, the present invention will be described on the basis of a preferred exemplary embodiment with reference to the drawings. The exemplary embodiment is an exemplification and does not limit the invention. All technical features described in the exemplary embodiment and combinations of these technical features are not always essential to the invention. The same or equivalent configuration elements, members, and processing illustrated in the drawings are denoted by the same reference numerals, and redundant description will be omitted as appropriate. Additionally, the scale and shape of each part illustrated in each drawing are set for convenience in order to facilitate the description, and are not limitedly interpreted unless otherwise specified. Additionally, when terms such as “first” and “second” are used in the present specification or claims, unless otherwise specified, these terms do not represent any order or importance, and are intended to distinguish one configuration from another configuration. Additionally, in each drawing, some members that are not important for describing the exemplary embodiment are omitted. 
       FIG. 1  is an exploded perspective view of a battery module having a support plate according to an exemplary embodiment.  FIG. 2  is a plan view of the battery module. Note that in  FIG. 1 , output terminal  22 , support plate  28 , bus bar  42 , and voltage detection line  46  are simplified. In  FIG. 2 , support plate  28  and voltage detection line  46  are simplified, and only some batteries  14  are shown by broken lines. Additionally, side separators  10 , constraining member  12 , and cover plate  60  are omitted. 
     Battery module  1  includes battery stack  2 , a pair of end plates  4 , cooling plate  6 , heat conductive layer  8 , side separators  10 , constraining members  12 , support plate  28 , voltage detection line  46 , and cover plate  60 . 
     Battery stack  2  includes a plurality of batteries  14  and inter-cell separators  16 . Each battery  14  is a rechargeable secondary battery such as a lithium-ion battery, a nickel-hydrogen battery, or a nickel-cadmium battery, for example. Additionally, each battery  14  is a so-called prismatic battery, and has exterior can  18  having a flat rectangular-parallelepiped shape. Exterior can  18  has a substantially rectangular opening (not illustrated) on one surface of exterior can  18 . An electrode assembly, an electrolyte, and the like are housed in exterior can  18  through the opening. Sealing plate  20  that closes the opening of exterior can  18  is disposed in the opening. 
     Output terminal  22  of a positive electrode is disposed on sealing plate  20  at a position close to one end of sealing plate  20  in a longitudinal direction, and output terminal  22  of a negative electrode is disposed on sealing plate  20  at a position close to the other end of sealing plate  20  in the longitudinal direction. The pair of output terminals  22  are respectively electrically connected to positive electrode plates and negative electrode plates that form the electrode assembly. Hereinafter, output terminal  22  of the positive electrode is referred to as positive-electrode terminal  22   a , and output terminal  22  of the negative electrode is referred to as negative-electrode terminal  22   b  as appropriate. Additionally, when there is no need to distinguish polarities of output terminals  22  from each other, positive-electrode terminal  22   a  and negative-electrode terminal  22   b  are collectively referred to as output terminals  22 . 
     Exterior can  18 , sealing plate  20 , and output terminals  22  are electric conductors and are made of metal, for example. Sealing plate  20  and the opening of exterior can  18  are joined to each other by, for example, laser welding. Each output terminal  22  is inserted into a through-hole (not illustrated) formed in sealing plate  20 . A seal member (not illustrated) having an insulating property is interposed between each output terminal  22  and the through-hole. 
     In the description of the present exemplary embodiment, for convenience, sealing plate  20  is referred to as an upper surface of battery  14 , and a bottom surface of exterior can  18  disposed on a side opposite to sealing plate  20  is referred to as a lower surface of battery  14 . Additionally, battery  14  has two main surfaces that connect the upper surface and the lower surface of battery  14  to each other. The main surfaces are surfaces that have the largest area among six surfaces of battery  14 . Additionally, the main surfaces are long side surfaces that are connected to long sides of the upper surface and long sides of the lower surface. Two remaining surfaces other than the upper surface, the lower surface, and the two main surfaces are referred to as side surfaces of battery  14 . These side surfaces are a pair of short side surfaces that are connected to short sides of the upper surface and short sides of the lower surface. 
     Additionally, for convenience, in battery stack  2 , surfaces of batteries  14  closer to an upper surface are referred to as an upper surface of battery stack  2 , surfaces of batteries  14  closer to a lower surface are referred to as a lower surface of battery stack  2 , and surfaces of batteries  14  closer to side surface are referred to as side surfaces of battery stack  2 . These directions and positions are defined for convenience unless otherwise specified. Accordingly, for example, the part defined as the upper surface in the present invention is not always positioned above the part defined as the lower surface. 
     Valve  24  is disposed on sealing plate  20  between the pair of output terminals  22 . Valve  24  is also referred to as a safety valve. Valve  24  is a mechanism which allows each battery  14  to blow off a gas in battery  14 . Valve  24  is configured to release the internal gas by opening valve  24  when the internal pressure of exterior can  18  is increased to a predetermined value or more. For example, valve  24  is formed of: a thin part that is formed on a part of sealing plate  20  and is thinner than other parts of valve  24 ; and a linear groove formed on a surface of the thin part. In this configuration, when the internal pressure of exterior can  18  increases, the thin part is torn from the groove to open valve  24 . Valves  24  of batteries  14  are connected to exhaust duct  38  described later, and the gas in the battery is discharged from valve  24  to exhaust duct  38 . 
     Additionally, each battery  14  has insulating film  26 . Insulating film  26  is, for example, a cylindrical shrink tube, and is heated after exterior can  18  is inserted in insulating film  26 . As a result, insulating film  26  shrinks and covers two main surfaces, two side surfaces, and a bottom surface of exterior can  18 . Insulating film  26  can prevent a short circuit between adjacent batteries  14  or a short circuit between battery  14  and end plate  4  or constraining member  12 . 
     The plurality of batteries  14  are stacked at predetermined intervals with the main surfaces of adjacent batteries  14  facing each other. Note that the term “stack” means that a plurality of members are arranged in any one direction. Accordingly, stacking of batteries  14  also includes an arrangement of the plurality of batteries  14  in a horizontal direction. In the present exemplary embodiment, batteries  14  are stacked horizontally. Accordingly, stacking direction X of batteries  14  is a direction extending horizontally. Hereinafter, when appropriate, a direction that is horizontal and is perpendicular to stacking direction X is referred to as horizontal direction Y, and a direction that is perpendicular to stacking direction X and horizontal direction Y is referred to as vertical direction Z. 
     Additionally, batteries  14  are disposed in a state where output terminals  22  are directed in the same direction. In the present exemplary embodiment, batteries  14  are disposed in a state where output terminals  22  are directed upward in the vertical direction. Additionally, when adjacent batteries  14  are connected in series, batteries  14  are stacked such that positive-electrode terminal  22   a  of one battery  14  and negative-electrode terminal  22   b  of another battery  14  are disposed adjacently to each other. Additionally, when adjacent batteries  14  are connected in parallel, batteries  14  are stacked such that positive-electrode terminal  22   a  of one battery  14  and positive-electrode terminal  22   a  of another battery  14  are disposed adjacently to each other. 
     Inter-cell separator  16  is also referred to as an insulating spacer, and is formed of a resin sheet having an insulating property, for example. Examples of the resin used for forming inter-cell separator  16  include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE). Inter-cell separator  16  is disposed between two adjacent batteries  14  to electrically insulate two batteries  14  from each other. 
     Battery stack  2  is sandwiched between the pair of end plates  4  in stacking direction X of batteries  14 . The pair of end plates  4  are disposed at both ends of battery stack  2  in stacking direction X of batteries  14 . The pair of end plates  4  are disposed adjacently to batteries  14  positioned at both ends of battery stack  2  in stacking direction X with external end separator  5  interposed between end plate  4  and battery  14 . External end separator  5  can be made of the same resin material as inter-cell separator  16 . Each end plate  4  is a metal sheet made of metal such as iron, stainless steel, or aluminum. By interposing external end separator  5  between end plate  4  and battery  14 , end plate  4  and battery  14  are electrically insulated from each other. Each end plate  4  has fastening holes  4   a  on two surfaces that are directed in horizontal direction Y. 
     Support plate  28  is placed on the upper surface of battery stack  2 . Support plate  28  is a plate-shaped member that supports voltage detection line  46 . Voltage detection line  46  is a member for detecting the voltage of battery  14 . Support plate  28  includes base plate  33  extending along the upper surface of battery stack  2 , and voltage detection line  46  is placed on base plate  33 . 
     Base plate  33  covers the upper surface of battery stack  2 , that is, a surface on which valve  24  of each battery  14  is disposed. Base plate  33  has a plurality of openings  32  through which valves  24  are exposed at positions corresponding to valves  24  formed on respective batteries  14 . Additionally, support plate  28  has exhaust duct  38  that temporarily stores the gas blown off from batteries  14 . Accordingly, support plate  28  also functions as a so-called duct plate. Exhaust duct  38  extends in stacking direction X of batteries  14  and is connected to valves  24  of respective batteries  14 . Each valve  24  communicates with exhaust duct  38  through opening  32 . 
     Exhaust duct  38  is defined by: first wall part  34  that covers the upper sides of the plurality of openings  32 ; and a pair of second wall parts  36  which surround the sides of openings  32 . The pair of second wall parts  36  are arranged in horizontal direction Y with the plurality of openings  32  interposed between the pair of second wall parts  36 . First wall part  34  faces valves  24 . The pair of second wall parts  36  protrude from base plate  33  toward cover plate  60 , and form both side surfaces of exhaust duct  38 . First wall part  34  is fixed to upper ends of the pair of second wall parts  36  to form a top surface of exhaust duct  38 . 
     Additionally, base plate  33  has openings  40  through which output terminals  22  are exposed at positions corresponding to output terminals  22  of batteries  14 . Bus bars  42  are placed on respective openings  40 . The plurality of bus bars  42  are supported by support plate  28 . Accordingly, support plate  28  also functions as a so-called bus bar plate. Bus bar  42  placed on each opening  40  electrically connects output terminals  22  of adjacent batteries  14 . 
     Support plate  28  of the present exemplary embodiment is made of a resin such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE) except for first wall part  34 . First wall part  34  is made of metal such as iron or aluminum. Additionally, the pair of second wall parts  36  are integrally formed with base plate  33  by molding. First wall part  34  is fixed to the pair of second wall parts  36  by fastening members (not illustrated) such as screws. 
     Bus bar  42  is a substantially strip-shaped member made of metal such as copper or aluminum. One end of bus bar  42  is connected to output terminal  22  of one battery  14 , and the other end of bus bar  42  is connected to output terminal  22  of another battery  14 . Bus bar  42  and output terminal  22  are joined by laser welding, for example. Bus bars  42  may connect output terminals  22  of the same polarity of a plurality of adjacent batteries  14  in parallel to form a battery block, and bus bars  42  may connect the battery blocks in series. Each of bus bars  42  connected to output terminals  22  of batteries  14  positioned at both ends in stacking direction X has external connection terminal  44 . External connection terminal  44  is connected to an external load (not illustrated). 
     Voltage detection line  46  placed on base plate  33  of support plate  28  is electrically connected to the plurality of bus bars  42  to detect the voltage of each battery  14 . Voltage detection line  46  has a plurality of conductive wires  76  and a plurality of tab terminals  78 . The plurality of conductive wires  76  are associated with respective bus bars  42 . One end of each conductive wire  76  is electrically connected to corresponding bus bar  42  by tab terminal  78 . Each tab terminal  78  has a substantial strip shape, and one end of tab terminal  78  is placed on bus bar  42  and is joined to bus bar  42  by laser welding, for example. The other end of each tab terminal  78  is joined to conductive wire  76  by clinching or soldering, for example. 
     The other end of conductive wire  76  is connected to connector  48 . Connector  48  is connected to an external battery ECU (not illustrated) or the like. The Battery ECU controls detection of the voltage or the like of each battery  14 , charging and discharging of each battery  14 , and the like. Additionally, some of the conductive wires  76  electrically connect external connection terminal  44  and connector  48 . 
     Cooling plate  6  has a flat plate shape extending in stacking direction X and in horizontal direction Y, and is made of a material having a high heat transfer property such as aluminum. Cooling plate  6  is connected to battery stack  2  in a heat-exchangeable manner to cool batteries  14 . Battery stack  2  is placed on cooling plate  6  with the lower surface of battery stack  2  facing cooling plate  6 . Cooling plate  6  may be connected to the outside of battery module  1  in a heat-exchangeable manner. Additionally, a flow path through which a refrigerant such as water or ethylene glycol flows may be formed in cooling plate  6 . 
     Heat conductive layer  8  is an insulative member interposed between battery stack  2  and cooling plate  6 . Heat conductive layer  8  covers the entire bottom surface of battery stack  2 . Heat conductive layer  8  can be formed of, for example, a known resin sheet having a good heat transfer property, such as an acrylic rubber sheet or a silicone rubber sheet. Additionally, heat conductive layer  8  may be made of a known adhesive agent, grease, or the like having a good heat transfer property and a good insulating property. Note that when exterior can  18  is sufficiently insulated by insulating film  26  or the like, heat conductive layer  8  does not need to have an insulating property. 
     Side separators  10  are members that have an insulating property and insulate constraining member  12  and battery stack  2  from each other. In the present exemplary embodiment, the pair of side separators  10  are arranged in horizontal direction Y. Battery stack  2 , the pair of end plates  4 , cooling plate  6 , and heat conductive layer  8  are disposed between the pair of side separators  10 . Each side separator  10  is made of, for example, a resin having an insulating property. Examples of the resin forming side separator  10  include the same thermoplastic resin as inter-cell separator  16 . 
     Side separator  10  of the present exemplary embodiment has first part  50 , second part  52 , and third part  53 . First part  50  has a rectangular flat plate shape, and extends in stacking direction X of batteries  14  along the side surface of battery stack  2 . Second part  52  has a strip shape extending in stacking direction X, and protrudes toward battery stack  2  from a lower side of first part  50 . Third part  53  has a strip shape extending in stacking direction X, and protrudes toward battery stack  2  from an upper side of first part  50 . Battery stack  2 , cooling plate  6 , and heat conductive layer  8  are disposed between second part  52  and third part  53 . 
     Constraining member  12  is also referred to as a bind bar, and is an elongated member that is long in stacking direction X of batteries  14 . In the present exemplary embodiment, the pair of constraining members  12  are arranged in horizontal direction Y Each constraining member  12  is made of metal. Examples of metal used for forming constraining member  12  include iron, stainless steel, and the like. Battery stack  2 , the pair of end plates  4 , cooling plate  6 , heat conductive layer  8 , and the pair of side separators  10  are disposed between the pair of constraining members  12 . 
     In the present exemplary embodiment, constraining member  12  has flat surface part  54  and a pair of arm parts  56 . Flat surface part  54  has a rectangular shape, and extends in stacking direction X along the side surface of battery stack  2 . The pair of arm parts  56  protrude toward battery stack  2  from ends of flat surface part  54  on both sides in vertical direction Z. Battery stack  2 , cooling plate  6 , heat conductive layer  8 , and side separator  10  are disposed between the pair of arm parts  56 . 
     Contact plate  68  is fixed to a region of flat surface part  54  that faces each end plate  4  by welding or the like. Contact plate  68  is provided with through-holes  70  at positions corresponding to fastening holes  4   a  of end plate  4 . Additionally, flat surface part  54  has through-holes  58  at positions corresponding to through-holes  70  of contact plate  68 . 
     By making the pair of end plates  4  engage with flat surface parts  54  of respective constraining members  12 , the plurality of batteries  14  are sandwiched between end plates  4  in stacking direction X. Specifically, battery stack  2  is formed by alternately arranging the plurality of batteries  14  and the plurality of inter-cell separators  16 , and such battery stack  2  is sandwiched between the pair of end plates  4  in stacking direction X with external end separators  5  interposed between battery stack  2  and end plates  4 . Additionally, heat conductive layer  8  and cooling plate  6  are disposed on a lower surface of battery stack  2 . In such a state, battery stack  2 , the pair of end plates  4 , cooling plate  6 , and heat conductive layer  8  are sandwiched between the pair of side separators  10  in horizontal direction Y. Further, the pair of constraining members  12  sandwich the whole body in horizontal direction Y from the outside of the pair of side separators  10 . 
     The pair of end plates  4  and the pair of constraining members  12  are positioned with respect to each other such that fastening holes  4   a , through-holes  70 , and through-holes  58  are aligned. Then, fastening members  59  such as screws are inserted into through-holes  58  and through-holes  70  to be threadedly engaged with fastening holes  4   a . As a result, the pair of end plates  4  and the pair of constraining members  12  are fixed to each other. By engaging the pair of end plates  4  with the pair of constraining members  12 , the plurality of batteries  14  are clamped and constrained in stacking direction X. 
     Additionally, constraining members  12  sandwich the plurality of batteries  14  in stacking direction X. Constraining members  12  also sandwich battery stack  2 , heat conductive layer  8 , and cooling plate  6  in the arrangement direction of battery stack  2 , heat conductive layer  8 , and cooling plate  6 . Specifically, battery stack  2 , heat conductive layer  8 , and cooling plate  6  are sandwiched between the pair of arm parts  56  of constraining member  12  in vertical direction Z. That is, constraining members  12  have both a function of fastening the plurality of batteries  14  and a function of fastening battery stack  2  and cooling plate  6 . 
     In a state where the pair of constraining members  12  are fixed to the pair of end plates  4 , first part  50  of side separator  10  is interposed between the side surface of battery stack  2  and flat surface part  54  of constraining member  12 . As a result, the side surfaces of batteries  14  and flat surface part  54  are electrically insulated from each other. Second part  52  of side separator  10  is interposed between cooling plate  6  and lower arm part  56  of constraining member  12 . As a result, cooling plate  6  and lower arm part  56  of constraining member  12  are electrically insulated from each other. Third part  53  of side separator  10  is interposed between the upper surface of battery stack  2  and upper arm part  56  of constraining member  12 . As a result, the upper surfaces of batteries  14  and upper arm part  56  of constraining member  12  are electrically insulated from each other. 
     As an example, after assembly of these constituent elements is completed, support plate  28  is placed on battery stack  2 . Support plate  28  is fixed to battery stack  2  by engaging third parts  53  of the pair of side separators  10  with support plate  28 . Then, bus bar  42  is placed on output terminals  22  of batteries  14 . Additionally, voltage detection line  46  is placed on support plate  28 . Subsequently, conductive wire  76  of voltage detection line  46  is electrically connected to each bus bar  42 . Thereafter, each bus bar  42  is electrically connected to output terminals  22 . 
     Cover plate  60  is placed on an upper surface of support plate  28 . Cover plate  60  is a plate-shaped member that is placed on support plate  28  to cover voltage detection line  46 . Cover plate  60  of the present exemplary embodiment is a so-called top cover that forms a part of an outer shell of battery module  1 , specifically, the upper surface of battery module  1 . Cover plate  60  prevents contact of dew water, dust, or the like with output terminals  22  and valves  24  of batteries  14 , bus bars  42 , voltage detection line  46 , and the like. 
     Cover plate  60  is made of a resin having an insulating property such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE), for example. Cover plate  60  has insulating cover parts  62  at positions overlapping external connection terminals  44  in vertical direction Z. In a state where cover plate  60  is placed on support plate  28 , external connection terminals  44  are covered with insulating cover parts  62 . 
     Both ends of cover plate  60  in horizontal direction Y are fixed to support plate  28 . Support plate  28  of the present exemplary embodiment has a plurality of engaging claws  72  spaced apart in stacking direction X at both ends of support plate  28  in horizontal direction Y. Additionally, cover plate  60  has engagement holes  74  at positions overlapping respective engaging claws  72  as viewed in vertical direction Z in base plate  61  extending along the upper surface of battery stack  2 . When cover plate  60  is placed on support plate  28 , engaging claws  72  are inserted into respective engagement holes  74 . As a result, both ends of cover plate  60  in horizontal direction Y are fixed to support plate  28  by snap-fitting. Support plate  28 , voltage detection line  46 , and cover plate  60  form voltage detection line module  47 . 
     Tab terminal  78  is joined to a substantially central part of bus bar  42  in stacking direction X. Alternatively, tab terminal  78  is joined to a region of bus bar  42  that straddles two batteries  14 . As a result, the amount of displacement of a joint between tab terminal  78  and bus bar  42  due to expansion and contraction of batteries  14  can be reduced. Hence, the connection state between tab terminal  78  and bus bar  42  can be maintained more stably. 
       FIG. 3  is a perspective view of a region including tab terminal  78  in voltage detection line module  47  according to the exemplary embodiment.  FIG. 4  is a perspective view schematically illustrating a region including tab terminal  78  in voltage detection line module  47 . Note that in  FIGS. 3 and 4 , cover plate  60  is omitted. 
     Support plate  28  includes position restricting structure  80  that determines the position of tab terminal  78 . Position restricting structure  80  has receiving surface part  82  against which tab terminal  78  abuts, and biasing part  84  that pushes tab terminal  78  toward receiving surface part  82 . 
     Conductive wire  76  of the present exemplary embodiment has connection end  76   a  connected to tab terminal  78 . Connection end  76   a  extends along an edge of opening  40 . Additionally, tab terminal  78  has fixing part  78   a  fixed to connection end  76   a  and joint  78   b  joined to bus bar  42 . Fixing part  78   a  extends in a first direction in which connection end  76   a  extends. One end side of fixing part  78   a  is fixed to connection end  76   a  by clinching, for example. Joint  78   b  extends from the other end of fixing part  78   a  in a second direction intersecting the first direction in which connection end  76   a  extends. Accordingly, tab terminal  78  has a rough L shape. 
     The base ends of connection end  76   a , fixing part  78   a , and joint  78   b  are placed on base plate  33 . The tip end of joint  78   b  overlaps bus bar  42  in vertical direction Z and is welded to bus bar  42 . In the present exemplary embodiment, the first direction corresponds to stacking direction X and the second direction corresponds to horizontal direction Y. Additionally, tab terminal  78  has opening  100  in a region (corner of L shape) where fixing part  78   a  and joint  78   b  are connected to each other. Base plate  33  has locking projection  102  at a position overlapping opening  100  in vertical direction Z. 
     Receiving surface part  82  and biasing part  84  are disposed so as to sandwich joint  78   b  in the first direction. Specifically, base plate  33  has wall part  86  extending along an edge of opening  40 . Wall part  86  is provided with cutout  88 , and joint  78   b  protrudes into opening  40  through cutout  88 . Wall part  86  has first side surface  90  and second side surface  92  facing each other with cutout  88  interposed between first side surface  90  and second side surface  92 . First side surface  90  forms receiving surface part  82 . 
     Biasing part  84  is provided on second side surface  92 . Biasing part  84  has support part  94  protruding toward first side surface  90  from the upper end of second side surface  92 , and hanging part  96  extending vertically downward from the tip end of support part  94 . Hanging part  96  is separated from second side surface  92  by the protruding amount of support part  94 . Accordingly, biasing part  84  has a spring structure including support part  94  and hanging part  96 . Base plate  33 , wall part  86 , and biasing part  84  of the present exemplary embodiment are integrally molded of resin. 
     Biasing part  84  has eaves part  98  protruding toward first side surface  90  on a surface of hanging part  96  facing first side surface  90 . Eaves part  98  overlaps joint  78   b  of tab terminal  78  when viewed in a third direction in which base plate  33  and voltage detection line  46  are arranged. In the present exemplary embodiment, the third direction corresponds to vertical direction Z. Eaves part  98  protrudes such that the amount of protrusion toward first side surface  90  gradually increases from cover plate  60  toward support plate  28 . 
     Tab terminal  78  is placed on base plate  33  while being positioned such that opening  100  overlaps locking projection  102 . At this time, locking projection  102  is inserted into opening  100 , and the attitude of tab terminal  78  with respect to base plate  33  is roughly determined. In the process of placing tab terminal  78  on base plate  33 , joint  78   b  is pushed into cutout  88  from the vertically upper side. At this time, the edge of joint  78   b  comes into contact with eaves part  98 , and biasing part  84  is pushed toward second side surface  92 . As a result, the lower end of hanging part  96  is displaced in a direction approaching second side surface  92  with support part  94  as a fulcrum. Consequently, the gap between biasing part  84  and receiving surface part  82  is increased, and joint  78   b  is sandwiched between biasing part  84  and receiving surface part  82 . 
     When joint  78   b  goes past eaves part  98 , the force by which joint  78   b  pushes eaves part  98  is canceled, and biasing part  84  is displaced in a direction separating from second side surface  92  by the elastic force of biasing part  84  itself. As a result, hanging part  96  comes into contact with joint  78   b  and presses joint  78   b  against receiving surface part  82 . Consequently, joint  78   b  is fixed to base plate  33 , and displacement of joint  78   b  is restricted. The protruding amount of biasing part  84  toward receiving surface part  82  is set such that, in a state where joint  78   b  is not fitted into cutout  88 , the distance between hanging part  96  and receiving surface part  82  is smaller than the dimension of a part of joint  78   b  sandwiched between hanging part  96  and receiving surface part  82 . As a result, joint  78   b  can be pressed against receiving surface part  82  more reliably. 
     Subsequently, bus bar  42  is pressed against output terminals  22  by a welding jig. In this state, a region of joint  78   b  overlapping bus bar  42  is irradiated with a laser beam, and joint  78   b  is welded to bus bar  42 . Thereafter, a region of bus bar  42  overlapping output terminals  22  is irradiated with a laser beam, and bus bar  42  is welded to output terminals  22 . After bus bar  42  is welded, cover plate  60  is attached to support plate  28 . 
       FIG. 5  is a cross-sectional view schematically illustrating a region including tab terminal  78  in voltage detection line module  47 . Cover plate  60  of the present exemplary embodiment has protrusion  104  protruding toward support plate  28 . Base plate  61  and protrusion  104  of the present exemplary embodiment are integrally molded of resin. Protrusion  104  is disposed so as to overlap eaves part  98  in vertical direction Z. In a state where cover plate  60  is placed on support plate  28 , the tip end of protrusion  104  abuts on eaves part  98 . Then, protrusion  104  pushes biasing part  84  toward second side surface  92  against the biasing force of biasing part  84 . As a result, the surface of hanging part  96  directed toward receiving surface part  82  is separated from joint  78   b.    
     As illustrated in  FIG. 3 , support plate  28  of the present exemplary embodiment has positioning projections  106 . Positioning projections  106  are disposed in a region of base plate  33  where conductive wire  76  is laid, and protrude toward cover plate  60 . When voltage detection line  46  is placed on support plate  28 , a part of conductive wire  76  in the vicinity of connection end  76   a  is positioned with positioning projections  106 . As a result, even when conductive wire  76  has a bending tendency, the extending direction of conductive wire  76  and connection end  76   a  can be restricted. Hence, joint  78   b  can be pressed against receiving surface part  82  more reliably by biasing part  84 . 
     As described above, support plate  28  according to the present exemplary embodiment includes base plate  33  on which voltage detection line  46  is placed, and position restricting structure  80  that restricts the position of tab terminal  78  of voltage detection line  46 . Position restricting structure  80  has receiving surface part  82  against which tab terminal  78  abuts, and biasing part  84  that pushes tab terminal  78  toward receiving surface part  82 . Additionally, voltage detection line module  47  of the present exemplary embodiment includes support plate  28  and voltage detection line  46 . As a result, positioning accuracy of voltage detection line  46  can be enhanced. More specifically, tab terminal  78  can be positioned accurately with respect to bus bar  42 . 
     By positioning tab terminal  78  accurately with respect to bus bar  42 , it is possible to avoid overlap of tab terminal  78  with a position on bus bar  42  where the welding jig is applied or a position where bus bar  42  and output terminal  22  are welded. Accordingly, manual adjustment of the position of tab terminal  78  by the operator can be omitted. Hence, welding can be adopted as a method of connecting voltage detection line  46  and bus bar  42 , and the connection of voltage detection line  46  to bus bar  42  can be automated. Consequently, the manufacturing process of battery module  1  can be simplified, and the cost of battery module  1  can be reduced. 
     Note that as a method of avoiding overlap of tab terminal  78  with a position on bus bar  42  where the welding jig is applied or a welding position of bus bar  42  and output terminal  22 , it is conceivable to reduce the size of tab terminal  78 . However, in this case, the welding area between tab terminal  78  and bus bar  42  may be reduced to lower the joining strength. On the other hand, according to the present exemplary embodiment, the manufacturing process of battery module  1  can be simplified while maintaining the joining strength between tab terminal  78  and bus bar  42 . 
     Additionally, tab terminal  78  of the present exemplary embodiment has joint  78   b  that extends in the second direction intersecting the first direction in which connection end  76   a  of conductive wire  76  extends and is joined to bus bar  42 . Then, receiving surface part  82  and biasing part  84  sandwich joint  78   b  in the first direction. With such a structure, the positioning accuracy of tab terminal  78  can be enhanced even more. 
     Additionally, biasing part  84  of the present exemplary embodiment has eaves part  98  overlapping tab terminal  78  when viewed in the third direction in which base plate  33  and voltage detection line  46  are arranged. As a result, displacement of tab terminal  78  in a direction separating from base plate  33  can be restricted. Hence, the positioning accuracy of tab terminal  78  can be enhanced even more. 
     Additionally, voltage detection line module  47  of the present exemplary embodiment includes cover plate  60  that is placed on support plate  28  and covers voltage detection line  46 . Cover plate  60  has protrusion  104  that presses biasing part  84  against its biasing force when cover plate  60  is placed on support plate  28 . As a result, biasing part  84  that is no longer required to press tab terminal  78  against receiving surface part  82  after tab terminal  78  is welded to bus bar  42  can be separated from tab terminal  78 . Consequently, it is possible to avoid generation of dust due to scraping of biasing part  84  caused by friction between metal tab terminal  78  and resin biasing part  84 . 
     The exemplary embodiment of the present invention has been described in detail above. The above-described exemplary embodiment is merely a specific example for carrying out the present invention. The contents of the exemplary embodiment do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of constituent elements can be made without departing from the spirit of the invention defined in claims. Novel exemplary embodiments with a design change acquire both advantageous effects of the exemplary embodiment and the modification that are combined with each other. In the above-described exemplary embodiment, the contents where such design changes are allowable are emphasized with expressions such as “of the present exemplary embodiment” and “in the present exemplary embodiment”. However, the design changes are also allowable in the contents which are not emphasized with such expressions. Any combination of constituent elements included in the exemplary embodiment is also effective as an aspect of the present invention. Hatching applied to cross sections in the drawings does not limit the material of the hatched object. 
     The exemplary embodiment may be specified by the item described below. 
     [Item 1] 
     A battery module including: 
     battery  14 ; 
     voltage detection line  46  including conductive wire  76  and tab terminal  78  and configured to detect a voltage of battery  14 ; and 
     support plate  28  that supports voltage detection line  46 , support plate  28  including base plate  33  on which voltage detection line  46  is placed, and position restricting structure  80  of tab terminal  78 , position restricting structure  80  including receiving surface part  82  against which tab terminal  78  abuts, and biasing part  84  that pushes tab terminal  78  toward receiving surface part  82 . 
     REFERENCE MARKS IN THE DRAWINGS 
     
         
         
           
               14  battery 
               22  output terminal 
               28  support plate 
               33  base plate 
               42  bus bar 
               46  voltage detection line 
               47  voltage detection line module 
               60  cover plate 
               76  conductive wire 
               76   a  connection end 
               78  tab terminal 
               78   b  joint 
               80  position restricting structure 
               82  receiving surface part 
               84  biasing part 
               98  eaves part 
               104  protrusion