Patent Publication Number: US-2020287194-A1

Title: Electrical connecting member housing case and battery module

Description:
TECHNICAL FIELD 
     The present invention relates to an electrical connecting member housing case, and to a battery module comprising such an electrical connecting member housing case. 
     BACKGROUND ART 
     A battery module is provided with a plurality of wires for detecting the voltage and temperature of the secondary battery, and these wires are bundled and housed in an electrical connecting part housing case (bus bar case) provided to the secondary battery. 
     As a structure of the wire housing space for housing the bundled wires, for instance, PTL 1 describes a wire housing frame characterized in that a locking protrusion is provided to an upper end outer side wall on the front side of the wire housing frame, an openable/closable lid is connected to a side wall on the back side of the frame via a hinge, a locking protrusion is provided to a lower end inner face of the lid end side wall which is bent downward from the end of the lid, and the front side wall locking protrusion is locked with a rib protruding toward the lower face of the lid. 
     Nevertheless, in a battery system for use in electrically driven vehicles in recent years, more battery cells are being used pursuant to cost reduction and miniaturization, and demanded is the further miniaturization of a battery system capable of more efficiently housing the wires. In light of the foregoing background, a more efficient wire housing structure is demanded. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Utility Model Registration No. 2583435 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     Conventionally, a wire housing space for housing the bundled wires was provided, for example, along the laminating direction of the secondary battery of the bus bar case, and, in certain cases, was provided by being separated into multiple rows. A bus bar case needs to be designed to be compact on the whole by giving consideration to the arrangement of the bus bar, terminal, and external terminal of the secondary battery module in addition to the wire housing space. 
     Nevertheless, with PTL 1, because the hinge is provided on the outer side of the wall forming the wire housing space, space for providing the lid and hinge is required, and there is a possibility that an efficient design may be difficult. 
     An object of the present invention is to provide an electrical connecting member housing case of a battery module capable of efficiently arranging wires such as voltage detection wires and temperature detection wires and realizing the miniaturization thereof by reducing, as much as possible, space for providing the lid and hinge around the wire housing space in the bus bar case. 
     Means to Solve the Problems 
     An electrical connecting member housing case including a wire housing space formed from a bottom part, a wall part, and a lid part, wherewith the wall part includes an outer wall, an end face, and an inner wall facing the wires, and wherein the lid part is connected to the wall part via a hinge part provided to the inner wall or the end face. 
     Advantageous Effects of the Invention 
     Because the present invention does not require space for providing the lid or hinge around the wire housing space, the present invention can provide an electrical connecting member housing case of a battery module capable of realizing the miniaturization thereof. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an external perspective view of the battery module according to Embodiment 1 of the present invention. 
         FIG. 2  is an exploded perspective view of the battery module shown in  FIG. 1 . 
         FIG. 3  is an external perspective view of the battery block shown in  FIG. 2 . 
         FIG. 4  is an external perspective view of the battery cell shown in  FIG. 3 . 
         FIG. 5  is a plan view in which a part of the top cover of the battery module shown in  FIG. 1  has been removed. 
         FIG. 6  is an exploded perspective view of the electrical connecting member housing case of the battery module  100  shown in  FIG. 5 , and is a diagram showing a state where the lid part of the wire housing space groove  80  is opened. 
         FIG. 7  is an exploded perspective view showing a state where the lid of the battery module wire housing space shown in  FIG. 5  is closed. 
         FIG. 8  is a cross sectional view in which a part of the cover of the battery module according to Embodiment 1 of the present invention has been removed. 
         FIG. 9  is a conceptual cross sectional view of the wire housing space according to conventional technology. 
         FIG. 10  is a conceptual cross sectional view of the wire housing space according to Embodiment 1 of the present invention. 
         FIG. 11  is a perspective view of  FIG. 10 . 
         FIG. 12  is a conceptual cross sectional view of the wire housing space according to a second embodiment of the present invention. 
         FIG. 13  is a conceptual cross sectional view of the wire housing space according to a third embodiment of the present invention. 
         FIG. 14  is a perspective view of  FIG. 13 . 
         FIG. 15  is a conceptual cross sectional view of the wire housing space according to a fourth embodiment of the present invention. 
         FIG. 16  is a separate example of the fourth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An embodiment of the battery module according to the present invention is now explained with reference to the appended drawings. 
     First Embodiment 
       FIG. 1  is an external perspective view of a battery module  100  according to Embodiment 1 of the present invention.  FIG. 2  is an exploded perspective view of the battery module  100  shown in  FIG. 1 . 
     The battery module  100  comprises a plurality of battery cells  10 , a plurality of voltage detection wires  20  connected to an external terminal  11  of each of the battery cells  10 , and a plurality of temperature detection wires  30  connected to the plurality of battery cells  10 . The plurality of battery cells have a flat shape, and are laminated by causing the broad-side faces to face each other. The battery module  100 , as shown in  FIG. 1 , comprises an electrical connecting part housing case  40  which covers a top face  10   a  of the plurality of battery cells  10 . Electric wires can be efficiently arranged by providing the electrical connecting part housing case  40  on the terminal side of the laminated secondary batteries. 
     As shown in  FIG. 1  and  FIG. 2 , the electrical connecting part housing case  40  includes, for example, an insulation cover  41  which is disposed to face the top face  10   a  of the plurality of battery cells  10  configuring a battery block  50 , and a top cover  42  which covers the upper part of the insulation cover  41 . The insulation cover  41  is provided with holes, and the external terminals  11  are inserted into these holes and connected to the bus bars provided to the insulation cover  41 . 
     The insulation cover  41  is prepared, for instance, from a resin material having insulation properties such as general-purpose resin (polypropylene or the like) or engineering plastic, and is a thin plate-shaped member which covers at least a part of the top face  10   a  of the plurality of battery cells  10 . The insulation cover  41  holds a plurality of bus bars  60  in a recessed portion, and electrically insulates the adjacent bus bars  60 . The bus bars  60  held in the recessed portion are connected to the terminals  11 . 
     The electrical connecting part housing case  40  houses a voltage detection wire  20  which detects the voltage of the battery cell  10 , and a temperature detection wire  30  which detects the temperature of the battery cell  10 . The voltage detection wire  20  and the temperature detection wire  30  are bundled and placed in a wire housing space groove  80  provided to the insulation cover  41 , and connected to a connector  21  through a tube  22 . Information of the voltage and information of the temperature are sent from the connector  21  to the outside of the battery module  100 . 
     The insulation cover  41  has an opening above a gas exhaust valve  15  of the plurality of battery cells  10  arranged in a single direction, and forms, with partition walls, a gas exhaust groove  44  which is in communication with the plurality of battery cells  10  in the laminating direction (X-axis direction). With the gas exhaust groove  44 , for example, the lower end thereof is opened to face the gas exhaust valve  15  of the plurality of battery cells  10 , includes a partition wall on either side of the gas exhaust valve  15  in the longitudinal direction of the top face  10   a  of the battery cells  10 , or in the transverse direction (Y-axis direction) of the battery block  50 . 
     The battery cell  10  is, for instance, a lithium ion secondary battery, and a flat square secondary battery having broad-side faces and narrow-side faces may be used as the battery cell  10 . The battery cells  10  are laminated in the thickness direction by causing the broad faces to face each other, and form a substantially rectangular parallelepiped battery block  50 . In the ensuing explanation, the respective components of the battery module  100  may be explained by using a rectangular coordinate system with the longitudinal direction of the battery block  50 , or the laminating direction of the battery cells  10 , as the X-axis direction, the transverse direction of the battery block  50  as the Y-axis direction, and the height direction of the battery block  50  as the Z-axis direction. 
       FIG. 3  is an external perspective view of the battery block  50  shown in  FIG. 2 . 
     The battery block  50  comprises a plurality of battery cells  10 , a cell holder  51  for holding each of the battery cells  10 , a pair of end plates  52  disposed on either end of the laminating direction of the plurality of battery cells  10 , and a pair of side plates  53  disposed on either side of the pair of end plates  52 . 
     The cell holder  51  is prepared, for example, from a resin material having insultation properties such as engineering plastic. The cell holder  51  is classified into a plurality of intermediate cell holders  51 A disposed between the battery cells  10 , and a pair of end cell holders  51 B disposed on either end of the plurality of battery cells  10  laminated via the plurality of intermediate cell holders  51 A. The cell holder  51  is disposed alternately with the battery cell in the laminating direction (X-axis direction) of the plurality of battery cells  10 , and the plurality of battery cells  10  are laminated in the thickness direction by sandwiching the individual battery cells  10  from either side in the thickness direction (X-axis direction). The intermediate cell holder  51 A also plays the role as a spacer which creates a space between two battery cells  10  which are adjacent in the laminating direction. 
     The battery cell  51  laminated together with the cell holder  51  is sandwiched by the pair of end plates  52  from either end in the laminating direction. The pair of end plates  52  is, for example, a metal member, or reinforced plastic, formed in a rectangular flat plate shape corresponding to the shape of the broad-side faces  12   a  of the battery container  12  configuring the battery cell  10 . 
     The battery cell  51  laminated together with the cell holder  51  is sandwiched by the pair of side plates  52  from the side of the narrow-side faces  12   b . A through hole through which a fastening member  54 , such as a bolt, is to be inserted is provided to either end of the side plate  52  in the longitudinal direction, and the side plate  53  and the end plate  52  are connected by the fastening member  54 , such as a bolt, through the through hole. Moreover, one end of the side plate  52  in the transverse direction is bent at a right angle in an L-shape, and the bent part is fitted with a groove part formed on the cell holder. Furthermore, by inserting the fastening member  54 , such as a bolt, through the through hole on either end in the longitudinal direction and fastening the fastening member  54  to the screw hole of the end plate  52 , the fastening member  54  is coupled to the pair of end plates  52 . 
       FIG. 4  is an external perspective view of the battery cell  10  shown in  FIG. 3 . 
     The battery cell  10  is, for example, a flat square lithium ion secondary battery, and includes a rectangular top face  10   a , a pair of external terminals  11  disposed by being separated from the top face  10   a  in the longitudinal direction (Y-axis direction), and a gas exhaust valve  15  provided between the pair of external terminals  11 . The battery cell  10  comprises, for example, a metal battery container  12  prepared from aluminum or an aluminum alloy. The battery container  12  is of a flat rectangular parallelepiped shape, and has broad-side faces  12   a  having a large area on either side in the thickness direction (X-axis direction), and narrow-side faces  12   b  having a small area on either side in the width direction (Y-axis direction). 
     The battery container  12  is configured, for example, from a bottomed square cylindrical battery can  13  in which the upper part thereof is opened, and a rectangular plate-shaped battery lid  14  for sealing the opening of the battery can  13 . The battery lid  14  is connected to the opening of the battery can  13 , for example, via laser welding. The inside of the battery container  12  houses, for example, a wound electrode group in which an electrode and a separator have been laminated and wound, a current collector which connects the electrodes of the wound electrode group and the pair of external terminals  11 , an insulation sheet which insulates the space between the wound electrode group and the battery container, and an electrolyte in which the wound electrode group is impregnated. 
     Of the pair of external terminals  11 , one is a positive electrode external terminal  11 P, and the other is a negative electrode external terminal  11 N. The pair of external terminals  11  is disposed separately at one end and the other end of the rectangular top face  10   a  of the battery cell  10 ; that is, in the longitudinal direction (Y-axis direction) of the rectangular top face  10   a  of the battery lid  14 , and is electrically insulated from the battery container  12  with a resin gasket  16  having insulation properties disposed between the battery lid  14  and the battery container  12 . 
     The gas exhaust valve  15  is provided between the pair of external terminals  11  disposed on the top face  10   a  of the battery cell  10 ; that is, the top face  10   a  of the battery lid  14 . The gas exhaust valve  15  is provided, for example, by pressing a center part of the battery lid  14  in the longitudinal direction and forming a thin-walled part formed on the battery lid  14 , and forming a slit groove on the thin-walled part. The gas exhaust valve  15  ensures the safety of the battery cell  10 , for example, by being opened when gas is generated within the battery container  12  due to an abnormality such as an overcharge of the battery cell  10  and the internal pressure of the battery container  12  increases beyond a predetermined pressure, and discharging the gas within the battery container  12  to the outside. 
     Moreover, the battery lid  14  includes a liquid injection hole  17  for injecting electrolyte into the battery container  12 , and a liquid injection plug  18  for sealing the liquid injection hole  17 . For example, by injecting electrolyte into the battery container  12  via the liquid injection hole  17  of the battery lid  14  and thereafter connecting the liquid injection plug  18  to the liquid injection hole  17  via laser welding, the liquid injection hole  17  can be sealed with the liquid injection plug  18 . 
     As shown in  FIG. 3 , the plurality of battery cells  10  configuring the battery block  50  are disposed such that the broad-side faces  12   a  of the battery container  12  are laminated in a manner of facing each other, and the gas exhaust valve  15  provided to the top face  10   a  of the battery cell  10 , and the external terminal  11 , are arranged in a single direction (X-axis direction) of the battery block  50 . More specifically, as a result of the gas exhaust valve  15  being provided at the center of the rectangular top face  10   a  of the battery cell  10  in the longitudinal direction (Y-axis direction), the gas exhaust valves  15  of the plurality of battery cells  10  are arranged in a line in the laminating direction (X-axis direction) of the plurality of battery cells  10 ; that is, the transverse direction (X-axis direction) of the rectangular top face  10   a  of the battery cell  10 , or the thickness direction (X-axis direction) of the battery cell  10 . Because the gas exhaust valves will be unified in a single direction by being arranged in the manner described above, the sites where gas is generated can be managed easily, and a duct may also be provided. Moreover, because the external terminals will be unified in a single direction, there is also an advantage in that the wires can be designed more easily. 
     Moreover, the plurality of battery cells  10  configuring the battery block  50  are laminated by being alternately inverted 180° so that, of the two battery cells  10  that are adjacent in the laminating direction, the positive electrode external terminal  11 P of one battery cell  10  and the negative electrode external terminal  11 N of the other battery cell  10  become adjacent in the laminating direction. The positive electrode external terminal  11 P and the negative electrode external terminal  11 N adjacent in the laminating direction of the plurality of battery cells  10  are connected via the bus bar  60  shown in  FIG. 2 . That is, the plurality of battery cells  10  are connected in series by a plurality of bus bars  60  which connect the positive electrode external terminal  11 P and the negative electrode external terminal  11 N adjacent in the laminating direction. The bus bars  60  are connected, for example, to the top face of the external terminal  11  of the battery cell  10  via laser welding. 
       FIG. 5  is a plan view showing a state where the top cover  42  of the battery module  100  shown in  FIG. 1  has been removed. 
     The battery module  100  of this embodiment comprises, as described above, a plurality of battery cells  10 , a plurality of voltage detection wires  20  connected to an external terminal  11  of each of the battery cells  10 , and a plurality of temperature detection wires  30  connected to the battery cells  10 . A gas exhaust groove  44 , which is communication in the laminating direction (X-axis direction), is formed at the center part in the longitudinal direction of the top face  10   a  of the battery cell  10 ; that is, in the transverse direction (Y-axis direction) of the battery block  50 , and a wire housing space groove  80  is provided in parallel adjacent to either side for housing the voltage detection wires  20  and the temperature detection wires  30 . 
     The wire housing space grooves  80  become an electrical connecting member housing case capable of housing wires such as voltage detection wires and temperature detection wires. 
     With the voltage detection wire  20 , one end is connected to the external terminal  11  of the individual battery cells  10  via the bus bar  60 , and the other end is connected to the connector  21 . The connector  21  is connected, for example, to a battery control unit (BCU). The BCU detects the voltage of the individual battery cells  10  via the plurality of voltage detection wires  20  connected to the external terminal  11  of the individual battery cells  10 . The plurality of voltage detection wires  20  are bundled, for instance, at the inner side of the opening  43  of the top cover  42 , and placed through a tube  22 . The tube  22  which covers the bundled plurality of voltage detection wires  20  extends, for example, from the inner side of the opening  43  of the top cover  42  to the connector  21  on the outer side of the cover  40 . 
     The temperature detection wire is connected to the plurality of battery cells  10  via a thermistor. In this embodiment, six temperature detection wires  30 , in which two wires form a pair, are connected to the top face  10   a  of three battery cells  10 . With the temperature detection wire  30 , one end is connected to the thermistor, and the other end is connected to the connector  31 . The thermistor connected to one end of the temperature detection wire  30  contacts the top face  10   a  of the battery cell  10 , in a manner of being pressed against thereto, by a pressing member provided to one end of the temperature detection wire  30 . 
     The connector  31  of the temperature detection wire  30  is also connected, for instance, to a BCU (battery control unit) in the same manner as the connector  21  of the voltage detection wire  20 . The BCU detects the temperature of the individual battery cells  10  in contact with the thermistor by detecting the voltage of the individual thermistors in contact with the top face  10   a  of the battery cell  10  with the temperature detection wires  30 , in which two wires form a pair, connected to the individual thermistors. The number of thermistors may be any number as required, and two, four or more thermistors may be provided to the battery module  100 . 
     The plurality of temperature detection wires  30  are bundled in the same manner as the voltage detection wires  20 , for instance, at the inner side of the opening  43  of the top cover  42 , and placed through a tube  33 . The tube  33  which covers the bundled plurality of temperature detection wires  30  extends, in the same manner as the tube  22  covering the bundled plurality of voltage detection wires  20 , for instance, from the inner side of the opening  43  of the top cover  42  to the connector  31  on the outer side of the cover  40 . 
       FIG. 6  is an exploded perspective view of the electrical connecting member housing case of the battery module  100  shown in  FIG. 5 , and is a diagram showing a state where the lid part of the wire housing space groove  80  has been opened. 
     A wire housing space groove  80  is formed on the connecting member housing case with a bottom part and a wall part  105 . The wall part  105  encompasses the wires, and a part thereof becomes a partition of the gas exhaust groove  44  and the wire housing space. The wall part  105  includes an inner wall facing the wires, and an outer wall, an end face, and a lid part which form the outer faces of the electrical connecting member housing case. The outer wall is facing a discharge groove  44 . Connected to the lid part  101  is an inner wall  105   a  or an end face  105   b  of the wall part  105  via a hinge part  104 .  FIG. 6  shows a state where the lid part  101  is opened upward, via the hinge  104 , from the inner wall of the wire housing space groove  80  of the wall part which partitions the wire housing space groove  80  housing the voltage detection wire  20  and the temperature detection wire  30 , and the gas exhaust groove  44 . 
     The lid part  101  has broad faces  101   a  and narrow faces  101   b , and one of the narrow faces  101   b  or a part of the broad faces  101   a  is connected to the hinge part  104 . 
       FIG. 7  is a diagram showing a state where the lid  101  in  FIG. 6  has been closed. 
     In  FIG. 7 , the lid  101  opened upward in  FIG. 6  opens the wire housing space grooves  80  housing the voltage detection wires  20  and the temperature detection wires  30  in a manner of facing the inner wall which is bent from the hinge part  104  to become a horizontal direction and which faces the narrow faces  101   b  on the counter-hinge side. The facing walls on the counter-hinge side may be provided with a stopping means for inhibiting the opening of the lid part  101 , such as the locking protrusion  102 , and the lid part  101  is locked by going over the locking protrusion  102 . 
     Moreover, a stopper  103  may be provided between the locking protrusion  102  of the wall part  105  and the bottom part  106  so that the wires are not damaged and excessive stress is not applied to the hinge part  104  as a result of the lid part  101  being bent downward below the protrusion  102  beyond a horizontal position. 
     Here, the lid  101  may be closed after housing the voltage detection wires  20  and the temperature detection wires  30  in the wire housing space groove  80 , or the lid part  101  may be locked with the locking protrusion  102  in advance before housing the voltage detection wires  20  and the temperature detection wires  30 , and the voltage detection wires  20  and the temperature detection wires  30  may be housed by bending the lid part  101  downward from the horizontal direction. However, in the foregoing case, the stopper  103  is not provided. 
     Because a gas exhaust valve is provided to the top face  10   a  of each of the battery cells  10 , the gas exhaust groove  44  is provided along the laminating direction (X-axis direction) of the battery cells  10 . The wire housing space grooves  80  are provided along the gas exhaust groove  44  on either side of the gas exhaust groove  44 . A plurality of voltage detection wires  20  are laid on one wire housing space groove  80 , and a temperature detection wire  30  is laid on the other wire housing space groove  80 . 
     More specifically, the wire housing space groove  80  can be configured from a plurality of second supporting parts  81  provided adjacent to the gas exhaust valve  15  in the transverse direction (Y-axis direction) of the battery block  50 ; that is, in the longitudinal direction of the top face  10   a  of the battery cells  10 . 
     The operation of the battery module  100  of this embodiment is now explained. 
     The battery module  100  of this embodiment is mounted, for example, on a hybrid vehicle or a plug-in hybrid vehicle which runs by using both an engine and a motor, or on an electrically driven vehicle such as an electric vehicle which runs by using only a motor. The battery module  100  supplies the electric energy accumulated in the plurality of battery cells  10 , for example, to an external device such as a motor, and accumulates the electric energy supplied, for example, from an external device such as a generator in the plurality of battery cells  10 , via the external connection terminal  61  shown in  FIG. 1  and  FIG. 2 . 
     Accordingly, with the battery module  100  comprising a plurality of battery cells  10  and which is mainly used by being mounted on vehicles, even more battery cells  10  are being used pursuant to the cost reduction and miniaturization of the battery cells  10 . When the number of battery cells  10  used in the battery module  100  increases, efficient wiring and a slimmer electrical connecting member housing case are required to deal with the increase in the number of voltage detection wires  20  and temperature detection wires  30  to be connected to the battery cells  10 . Thus, for example, with the wire housing frame described in PTL 1, because a hinge is provided to the housing outer side wall (corresponds to the outer wall  105   c ) of the side wall forming the housing frame, space for forming the lid via the hinge is required. Accordingly, when providing two rows of the wire housing space groove as shown in  FIG. 5 , a gap is required between the two wire housing space grooves for forming the lid to cover the respective housing frames, and, consequently, the wires cannot be efficiently arranged as a pair of parallel lines, and there is a possibility that the miniaturization of the battery module may become difficult. Moreover, when providing another member, such as a duct, adjacent to the wire housing space groove, because it is necessary to secure space at least for the hinge, there is a possibility that the size of the battery module will become enlarged by that much. 
       FIG. 8  is a cross sectional view of the A-cross section of  FIG. 5 . 
     An insulation cover  41  is provided to the top face  10   a  of the battery cell  10 , and a side plate  53  is provided to the side face. Holes into which the positive electrode external terminal  11 P and the negative electrode external terminal  11 N are to be respectively inserted are provided on either end of the insulation cover  41  in the transverse direction (Y direction). Two rows of the wire housing space groove  80  are provided between the respective holes into which the positive electrode external terminal  11 P and the negative electrode external terminal  11 N are to be inserted along the longitudinal direction of the insulation cover  41 . A gas exhaust groove  44  is provided between the two rows of the wire housing space groove  80 . The two rows of the wire housing space groove may separately house the temperature detection wires and the voltage detection wires, and they may be separately housed in the respective grooves. 
     The wall part  105  on the side of the gas exhaust groove  44  of the wire housing space groove  80  is a wall that forms the gas exhaust groove  44 , and a lid part  101  is provided to the wall part  105  via a hinge part  104 . The lid part  101  moves in the direction of the arrows shown in  FIG. 8 , and the wire housing space is closed with the lid part  101 . 
       FIG. 9  is a simplified diagram of the part of the wire housing space groove in the conventional technology. 
     The wire housing space groove  80  is a part of the insulation cover, and, for example, is integrally formed with the lid part  101  via resin injection molding. Because the hinge part  104  is formed on the outer wall  105   c  of the wall, it is necessary to provide space for the lid part and the hinge part, and this is a significant restraint in terms of design. Even when manufacturing the insulation cover  41 , it is necessary to provide space at the outer side of the wall (on the side of the outer wall  105   c ) as the injection mold for forming the lid part  101  and the hinge part  104  will be positioned above and below the insulation cover. 
     Moreover, because the hinge part  104  will be bent 180° upon closing the lid, the stress applied to the hinge part  104  will also be significant, and the tolerable range of the dimension setting and selection of applicable resin will also be limited. As the bent part of the hinge part  104  will protrude from the outer face of the wall of the wire housing space groove  80  after the lid is closed, this may become a restraint in terms of design or become the cause of hooking. Moreover, the strength of one side of the lid must be secured with a thin and soft hinge part  104  for protection against vibration or shock in a direction that is perpendicular to the hinge part  104  of the lid (vibration in the direction shown with the arrow of  FIG. 9 ). 
       FIG. 10  is a simplified diagram in which a part of the wire housing space groove  80  of first embodiment has been extracted. 
     The wire housing space groove  80  is a part of the insulation cover  41 , and, for example, is integrally formed with the lid part  101  via resin injection molding. The wire housing space groove  80  includes a bottom part  106  which is integrally formed with the side of the insulation cover  41 , a wall part  105 , and a lid part  101  which is connected to the wall part  105 . 
     Wires such as the voltage detection wires  20  and the temperature detection wires  30  are housed in the wire housing space formed with the bottom part  106  and the wall part  105 . The wall part  105  includes an inner wall  105   a  as a wall on the inner side facing the wires, an end face  105   b  formed on the end of the wall, and an outer wall  105   c  as a face on the outer side. The hinge part  104  is provided to the inner wall  105   a , and connects the wall part  105  and the lid part  101 . Because the hinge part  104  is provided to the inner wall  105   a , which is the inner side of the wall part  105 , there is no influence on the outer side of the wires of the wall, and can be designed without any restraint. Thus, as shown in  FIG. 5 , the bus bar, the wire housing space grooves  80 , and the gas exhaust groove  44  can be efficiently arranged in the insulation cover  41 . The insulation cover  41  is provided with a recess for holding the bus bars  60  on either end in the transverse direction (Y direction). The adjacent bus bars  60  are electrically insulated from each other. The wire housing space grooves  80  are respectively provided in parallel to the inner side of the recess, and a gas exhaust groove  44  is disposed between the two rows of the wire housing space groove  80 . Because the bent part of the hinge part  104  will not protrude from the outer face of the wall of the wire housing space groove  80  after the lid part  101  is closed, the design can be created without having to consider the foregoing protrusion of the hinge part  104  (other members can be placed adjacent to the outer wall  105   c ), an efficient design can be realized. 
     The degree of freedom of design around the outer side of the wire housing space will improve, and a wire housing space can be additionally provided adjacently, and a plurality of temperature detection wires can be laid along a single direction in which the gas exhaust valves are aligned. Thus, according to the present invention, it is possible to provide a battery module capable of dealing with the increase in the voltage detection wires and temperature detection wires associated with the increase in the number of battery cells, and realizing the miniaturization thereof. 
     The inner wall  105   a  facing the inner wall, which is provided with the hinge part  104 , is provided with a locking protrusion  102  provided on the side of the end face  105   b  of the wall part  105 , and a stopper  103  provided to the side of the bottom part  106  of the wall part  105 . In a state where the lid part  101  is closed, the locking protrusion  102  is facing the face on the outer side of the broad face  101   a  of the lid part  101 , and the stopper  103  is facing the face on the inner side of the broad face  101   a . The locking protrusion  102  prevents the lid part  101  from opening, and the stopper  103  prevents the lid part  101  from moving toward the deep end of the space. 
     The lid part  101  has a a pair of broad faces  101   a  and a pair of narrow faces  101   b , and the hinge is connected to the broad face  101   a  on the outer side of the space. Accordingly, because the lid part  101  will face upward in a state where the lid part  101  is open, there is no influence on the other members in a state where the lid is open. 
     Moreover, with the lid part  101 , because the narrow faces  101   b  are facing the inner wall  105   a  in a state where the wire housing space  80  is closed, the lid part  101  can obtain a reaction from the inner wall  105   a  (force in the direction of the arrow shown in  FIG. 10 ), and, because both narrow faces  101   b  will be sandwiched with either wall face, the lid part  101  will have a strong structure against vibration in a direction that is horizontal to the insulation cover. 
     Moreover, as the lid part  101  will be pressed against the locking side wall part due to the reactive force of the hinge part  104 , the lid part  101  will be more reliably locked with the locking protrusion  102 , and the degree of freedom of the gap between either narrow face and either wall face of the lid part  101  will also increase. 
     As described above, according to the battery module  100  of this embodiment, it is possible to deal with the increase in the voltage detection wires  20  and the temperature detection wires  30  associated with the increase in the number of battery cells  10  and realize the miniaturization of the battery module  100 , as well as more firmly and reliably close the wires. 
       FIG. 11  is a perspective view in a state where the lid part of  FIG. 10  has been opened. 
     Second Embodiment 
       FIG. 12  is a simplified diagram of the wire housing space groove  80  of the second embodiment. As with the first embodiment, the wire housing space groove  80  is a part of the insulation cover, and is integrally formed with the lid part  101  via resin injection molding. 
     In the second embodiment, the hinge part  104  of the first embodiment connects the end face  105   b  of the wall part  105  and the narrow face  101   b  of the lid part  101 . Note that, because the remaining structure of the battery module  100  of the first embodiment and the second embodiment is the same, the explanation thereof is omitted. 
     In a state where the lid part  101  is open, the lid part  101  is erected upward (perpendicular direction) relative to the bottom part  106 . While the hinge  104  may be provided anywhere on the end face  105   b , preferably, the hinge  104  is provided to the inner wall side  105   a  of the end face  105   b  along the inner wall  105   a  (as an extension of the inner wall) in a state where the lid part  101  is open. As a result of providing the hinge part in the foregoing manner, there are advantages in that the shape of the mold can be simplified (because when there is a recess in the inner face of the wall, it may be necessary to use a slide-type mold), and the hinge part can be shortened. 
     According to the battery module  100  of the second embodiment, in addition to yielding the same effects as the battery module  100  of the first embodiment, there are the following advantages. The thickness of the hinge part  104  needs to be reduced in comparison to its periphery to facilitate the bending thereof, and an appropriate thickness is roughly 0.05 to 0.3 mm. Thus, it may become difficult for the resin to flow in the injection molding, and in particular the resin flow direction in the hinge part  104  in Embodiment 1 will become perpendicular, which will obstruct the force of the resin flow and inhibit the propagation of the resin pressure. However, according to this embodiment, because the force of the hinge part  104  is not blocked along the resin flow and the resin pressure can be easily propagated, resin can be easily filled in the lid part. 
     With the lid part  101 , because the narrow face  101   b  is facing the inner wall  105   a  in a state where the wire housing space  80  is closed, the lid part  101  can obtain a reaction from the inner wall  105   a , and, because both narrow faces  101   b  will be sandwiched with either wall face, the lid part  101  will have a strong structure against vibration in a direction that is horizontal to the insulation cover. 
     Third Embodiment 
       FIG. 13  is a simplified diagram of the wire housing space groove  80  of the third embodiment. As with the first embodiment, the wire housing space groove  80  is a part of the insulation cover, and is integrally formed with the lid part  101  via resin injection molding. 
     In the third embodiment, the hinge part  104  of the first embodiment connects the inner wall  105   a  of the wall part  105  and the narrow face  101   b  of the lid part  101 . Note that, because the remaining structure of the battery module  100  of the first embodiment and the second embodiment is the same, the explanation thereof is omitted. The lid part  101  has a structure of facing diagonally upward, in an open state, relative to the bottom part  106 . As a result of adopting this kind of structure, because the bend of the hinge part  104  can be reduced by that much upon closing the wire housing space groove  80 , the stress of the hinge part  104  can be alleviated. Moreover, because the wall thickness of the hinge part  104  can also be increased, the resin flow during molding can be improved, and the options of applicable resin can also be increased. 
     Moreover, with the lid part  101 , because the narrow face  101   b  is facing the inner wall  105   a  in a state where the wire housing space  80  is closed, the lid part  101  can obtain a reaction from the inner wall  105   a , and, because both narrow faces  101   b  will be sandwiched with either wall face, the lid part  101  will have a strong structure against vibration in a direction that is horizontal to the insulation cover. 
       FIG. 14  is a perspective view in a state where the lid of  FIG. 13  has been opened. 
     Fourth Embodiment 
       FIG. 15  is a simplified diagram of the wire housing space groove  80  of the fourth embodiment. As with the first embodiment, the wire housing space groove  80  is a part of the insulation cover, and is integrally formed with the lid part  101  via resin injection molding. 
     In the fourth embodiment, the hinge part  104  in the first embodiment is connected to the inner wall  105   a  of the wall part  105  and the narrow faces  101   b  of the lid part  101 . Otherwise, as shown in  FIG. 16 , the end  105   b  of the wall part  105  and the narrow faces  101   b  of the lid part  101  may also be connected. Because the remaining structure is the same as the remaining structure of the battery module  100  of the first embodiment and the second embodiment, the explanation thereof is omitted. 
     The lid part  101  is in a horizontal state relative to the bottom part  106  in an open state and in a closed state. By setting the lid part  101  to be horizontal, the mold shape can be further simplified. Moreover, because stress is not applied to the hinge  104  in a closed state, there is an advantage in that the resistance against deterioration is strong. Moreover, because a locking protrusion  102  is not particularly required, the structure can be simplified. Upon housing the voltage detection wires  20  and the temperature detection wires  30  in the wire housing space grooves  80 , for instance, the lid part  101  is housed by being pressed downward from a horizontal position. In the foregoing case, the stopper  103  is not provided. 
     Moreover, because the narrow faces  101   b  are facing the inner wall  105   a  in a state where the lid part  101  has closed the wire housing space  80 , the lid part  101  can obtain a reaction from the inner wall  105   a , and, because both narrow faces  101   b  are sandwiched by either wall face, the lid part  101  will have a strong structure against vibration in a direction that is horizontal to the insulation cover. 
     While the embodiments of the present invention have been explained in detail with reference to the appended drawings, the specific configuration is not limited to these embodiments, and any design change or the like within a range that does not deviate from the subject matter of the present invention shall be covered by the present invention. 
     REFERENCE SIGNS LIST 
     
         
           10  battery cell 
           10   a  top face 
           11  external terminal 
           11 N negative electrode external terminal 
           11 P positive electrode external terminal 
           12  battery container 
           12   a  broad-side face 
           12   b  narrow-side face 
           15  gas exhaust valve 
           16  gasket 
           17  liquid injection hole 
           18  liquid injection plug 
           20  voltage detection wire 
           21  connector (voltage detection wire) 
           22  tube (voltage detection wire) 
           30  temperature detection wire 
           31  connector (temperature detection wire) 
           33  tube (temperature detection wire) 
           40  electrical connecting part housing case 
           41  insulation cover 
           42  top cover 
           44  gas exhaust groove 
           45  harness cover 
           50  battery block 
           51  cell holder 
           51 A intermediate cell holder 
           51 B end cell holder 
           52  end plate 
           53  side plate 
           60  bus bar 
           61  external connection terminal 
           80  wire housing space groove 
           100  battery module 
           101  lid part 
           101   a  broad faces 
           101   b  narrow faces 
           102  locking protrusion 
           103  stopper 
           104  hinge part 
           105  wall part 
           105   a  inner wall 
           105   b  end face 
           105   c  outer wall 
           106  bottom part