Abstract:
An electric vehicle comprises an electric motor which generates a driving power for driving a wheel; a battery case accommodating a battery storing DC power to be supplied to the electric motor, in a battery space in an interior of the battery case; an inverter which converts the DC power supplied from the battery and supplies electric power to the electric motor; and an electric wire connecting the inverter to the electric motor, wherein the electric wire runs through an internal space of the battery case.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an electric vehicle which drives a wheel with driving power generated in an electric motor. 
       BACKGROUND ART 
       [0002]    In recent years, an electric vehicle which drives a wheel with driving power generated in an electric motor using electric power supplied from batteries has been developed. The electric vehicle includes an inverter (motor driving device) which drives the electric motor using the electric power supplied from the batteries, an electric wire (power line) connecting the batteries to the inverter, and an electric wire connecting the inverter to the electric motor (e.g., see Patent Literature 1). In an electric motorcycle disclosed in Patent Literature 1, the wire connecting the motor driving device to the motor extends in a forward and rearward direction along a swing arm. 
       CITATION LIST 
     Patent Literature 
       [0003]    Patent Literature 1: Japanese Laid-Open Patent Application Publication No. 2002-264664 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0004]    A current with a large magnitude flows among the batteries, the inverter, and the motor. In light of this, the electric wire is preferably placed in such a way that the electric wire is protected from an outside world and a driver of the electric vehicle is protected from the electric wire. If a protecting structure is provided additionally, the space efficiency of the electric vehicle may be reduced, or the external appearance of the electric vehicle may be degraded. 
         [0005]    Accordingly, an object of the present invention is to increase the space efficiency of an electric vehicle by laying out an electric wire connecting an inverter to an electric motor in a compact manner, while protecting the electric wire more effectively. 
       Solution to Problem 
       [0006]    The present invention provides an electric vehicle comprising: an electric motor which generates driving power for driving a wheel; a battery case accommodating a battery storing DC power to be supplied to the electric motor, in a battery space in an interior of the battery case; an inverter which converts the DC power supplied from the battery and supplies electric power to the electric motor; and an electric wire connecting the inverter to the electric motor, wherein the electric wire runs through an internal space of the battery case. 
         [0007]    In accordance with this configuration, since the electric wire (power line) connecting the inverter to the electric motor runs through the internal space of the battery case, this electric wire can be easily protected from outside and the space efficiency can be increased. In addition, since the electric wire can be covered by the battery case, the external appearance of the electric vehicle can be improved. 
         [0008]    The battery case may be placed between the electric motor and the inverter. 
         [0009]    In accordance with this configuration, a distance from the battery to the inverter and a distance from the battery to the electric motor can be reduced, and the electric wire connecting the inverter to the electric motor is allowed to run through the interior of the battery case, which can reduce the length of the electric wire. 
         [0010]    The electric vehicle may further comprise: a motor case accommodating the electric motor, wherein the inverter may be placed above the battery case, and the electric motor may be placed below the battery case, wherein the electric wire may include a running portion vertically running through the internal space of the battery case, and wherein an electric cable may be provided between a lower portion of the battery case and the motor case to couple the lower portion of the battery case to the motor case, the electric cable electrically connecting the running portion to the electric motor and having a higher flexibility than the running portion. 
         [0011]    In accordance with this configuration, even when the inverter and the electric motor are placed to be vertically spaced apart from each other with the battery case interposed between the inverter and the electric motor, the electric cable can be reduced in length and a wiring operation can be easily performed, as compared to a case where the electric wire runs through a region outside of the battery case. 
         [0012]    The electric wire may include three bus bars for three-phase AC current which vertically runs through the internal space of the battery case, and surfaces of the three bus bars may be joined to each other via an insulating material to form a bus bar module. 
         [0013]    In accordance with this configuration, the electric wire for a three-phase AC current can be accommodated in a compact manner in a limited space in the interior of the battery case, and can be handled more easily during assembly. In addition, since the elements of the electric wire are joined to each other via the insulating material, generation of noise in these elements of the electric wire can be suppressed. 
         [0014]    The electric wire may include a portion which runs through the interior of the battery case, penetrates an upper surface of the battery case, and protrudes upward, and the portion may be connected to the inverter placed on an upper portion of the battery case. 
         [0015]    In accordance with this configuration, since the electric wire running through the internal space of the battery case protrudes upward from the battery case, the inverter can be easily mounted later to the upper portion of the battery case which is closed. 
         [0016]    The battery may be one of a plurality of batteries, and in the internal space of the battery case, a cooling passage may be constituted by a space formed between the plurality of batteries or between the batteries and the battery case, and the electric wire may run through the cooling passage in the internal space of the battery case. 
         [0017]    In accordance with this configuration, since the space reserved to cool the battery is used as the space reserved to allow the electric wires to run therethrough, the size of the battery case is not increased. 
       Advantageous Effects of Invention 
       [0018]    As should be appreciated from the above, in accordance with the present invention, the space efficiency of an electric vehicle can be increased and the external appearance thereof can be improved by laying out an electric wire connecting an inverter to an electric motor in a compact manner while protecting the electric wire more effectively. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]      FIG. 1  is a left side view of an electric motorcycle according to an embodiment. 
           [0020]      FIG. 2  is a right side view of a power unit of the electric motorcycle of  FIG. 1 . 
           [0021]      FIG. 3  is an exploded perspective view of the power unit (electric motor device is not shown) of the electric motorcycle of  FIG. 1 , when viewed from the left and front. 
           [0022]      FIG. 4  is an exploded perspective view of the power unit (electric motor device is not shown) of the electric motorcycle of  FIG. 1 , when viewed from the right and rear. 
           [0023]      FIG. 5  is a longitudinal sectional view of the power unit (electric motor device is not shown) of the electric motorcycle of  FIG. 1 , when viewed from the left. 
           [0024]      FIG. 6  is a perspective view showing a state in which an ECU, a DC/DC converter, and the like in the region above a battery case of the electric motorcycle of  FIG. 1  are detached. 
           [0025]      FIG. 7  is a perspective view showing a state in which an inverter and the like in the region above the battery case of  FIG. 6  are further detached. 
           [0026]      FIG. 8  is a perspective view of major components for explaining a bus bar module in the interior of the battery case of the electric motorcycle of  FIG. 1 . 
           [0027]      FIG. 9  is a perspective view of a first bus bar module of  FIG. 8 . 
           [0028]      FIG. 10  is a perspective view of a second bus bar module of  FIG. 8 . 
           [0029]      FIG. 11  is a perspective view of a third bus bar module of  FIG. 8 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0030]    Hereinafter, the embodiment will be described with reference to the drawings. 
         [0031]      FIG. 1  is a left side view of an electric motorcycle  1  according to the embodiment of the present invention.  FIG. 2  is a right side view of a power unit  19  of the electric motorcycle  1  of  FIG. 1 . As shown in  FIGS. 1 and 2 , the electric motorcycle  1  which is a straddle-type electric vehicle includes a front wheel  2  which is a driven wheel, and a rear wheel  3  which is a drive wheel. The front wheel  2  is rotatably mounted to the lower end portion of a front fork  4 . The upper portion of the front fork  4  is integrated with a steering shaft (not shown). The steering shaft is rotatably supported by a head pipe  5  of a vehicle body in a state in which the steering shaft is inserted into the head pipe  5 . A bar-type handle  6  extending in a rightward and leftward direction is attached to the steering shaft, and an accelerator grip (not shown) is provided at the right side of the handle  6 . 
         [0032]    The vehicle body frame  10  of the electric motorcycle  1  includes a pair of right and left main frames  11  extending rearward from the head pipe  5  such that they are inclined slightly downward. A pair of right and left down frames  14  are coupled to the front end portions of the main frames  11 , respectively such that the down frames  14  extend downward therefrom, and then rearward. The rear end portions of the main frames  11  are connected to the upper portion of a pivot frame  12  of a frame shape. The front end portion of a swing arm  15  is mounted to the pivot frame  12  such that the swing arm  15  supports the rear wheel  3  and is vertically pivotable. A rear frame  13  is placed above the swing arm  15  and is connected to the rear end portions of the main frames  11 . A side stand  17  is placed at the left side of the pivot frame  12 . The side stand  17  can be tilted between a use position and a non-use position. In the use position, the side stand  17  supports the vehicle body of the electric motorcycle  1  such that the vehicle body is inclined to the right or to the left (in the present example, to the left). 
         [0033]    The vehicle body frame  10  supports the power unit  19  in a space formed between the head pipe  5  and the pivot frame  12 . The power unit  19  includes a plurality of batteries  40 , an electric motor  42 , an inverter  47  (see  FIG. 2 ), and others which are integrated. The plurality of batteries  40  are accommodated into a battery case  20 . The battery case  20  includes a middle case  21  which is made of metal and has a tubular shape in which upper and lower sides thereof are opened and the lower end of a rear section is closed, an upper case  22  which is made of a resin and attached to the middle case  21  to close an upper opening in the middle case  21 , and a lower case  23  which is made of a resin and attached to the middle case  21  to close a lower opening in the front section of the middle case  21 . 
         [0034]    A motor unit  25  is mounted to the battery case  20  in a location that is rearward relative to the lower case  23  and below the middle case  21 . Specifically, the motor unit  25  is fastened to a frame member  32  of the middle case  21  and the pivot frame  12  by brackets  36 ,  37 . The motor unit  25  includes a casing  44  (motor case), the electric motor  43  accommodated in the casing  44  to generate driving power for moving the vehicle body, a transmission  43  accommodated in the casing  44  to change the speed of a rotational driving power output from the electric motor  43 , an oil pan  44   a  attached to the lower portion of the casing  44 , and an oil pump  45  which suctions up and discharges oil stored in the oil pan  44   a . The rotational driving power output from the transmission  43  is transmitted to the rear wheel  3  via a chain  16 . 
         [0035]    An electric component cover  26  is attached to the upper surface of the battery case  20  to form an electric component space accommodating an electric component group  46 , together with the upper case  22 . The electric component cover  26  is insulative, and is made of, for example, an insulating resin material. The electric component cover  26  is covered by an upper cover  28  which is a dummy tank which looks like a fuel tank of a conventional engine-driven motorcycle. The upper cover  28  is made of, for example, a metal material. The electric component cover  26  is lower in strength than the upper cover  28  is. The rear portion of the upper cover  28  is formed with a connector opening  28  through which a charging connector  75  (see  FIG. 5 ), which will be described later, is exposed. The connector opening  28  is closed by a connector lid member  29 . The rear portion of the upper cover  28 , corresponding to the connector lid member  29 , is smaller in dimension in a vehicle width direction than the center portion of upper cover  28 , covering the electric component cover  26 . A driver seat  30  supported by the rear frame  13  is placed rearward relative to the upper cover  28 . The driver seated on the seat  30  can grip the upper cover  28  with their legs. The upper surface of the battery case  20  is located below the upper end of the seat  30 . In this configuration, even when the electric component group  46  including the inverter  47  and the like is placed on the battery case  20 , it becomes possible to lessen the amount of the electric component group  46  which protrudes upward from a virtual line connecting the seat  30  to the head pipe  5 . 
         [0036]    The batteries  40  are placed between the head pipe  5  and the seat  30 . At least a portion of the batteries  40  is placed above and forward relative to footrests of the vehicle body, and between the legs of the driver seated on the seat  30 . The electric motor  42  is placed between the head pipe  5  and the seat  30 . The electric motor  42  is supported on the pivot frame  12  and is configured not to be pivoted together with the swing arm  15 . The battery case  20  is positioned between the electric motor  42  and the inverter  47 . 
         [0037]    The casing  44  of the motor unit  25  is placed inward relative to the peripheral edge of the bottom surface of the battery case  20  when viewed from above, and the inverter  47  is placed inward relative to the peripheral edge of the upper surface of the battery case  20  when viewed from above. This makes it possible to prevent electric cables  27  connecting the inverter  47  to the electric motor  42  from protruding in the forward and rearward direction and the rightward and leftward direction of the battery case  20 . 
         [0038]      FIG. 3  is an exploded perspective view of the power unit  19  (the motor unit  25  is not shown) of the electric motorcycle  1  of  FIG. 1 , when viewed from the left and front.  FIG. 4  is an exploded perspective view of the power unit  19  (the motor unit  25  is not shown) of the electric motorcycle  1  of  FIG. 1 , when viewed from the right and rear.  FIG. 5  is a longitudinal sectional view of the power unit  19  (motor unit  25  is not shown) of the electric motorcycle  1  of  FIG. 1 , when viewed from the left.  FIG. 6  is a perspective view showing a state in which an ECU  54 , a DC/DC converter  50 , and the like in the region above the battery case  20  of the electric motorcycle of  FIG. 1  are detached.  FIG. 7  is a perspective view showing a state in which the inverter  47  and the like in the region above the battery case  20  of  FIG. 6  are further detached. 
         [0039]    As shown in  FIGS. 2 to 5 , the plurality of batteries  40  storing a DC power to be supplied to the electric motor  42  are aligned in a battery space S 2  in the interior of the battery case  20 . The plurality of batteries  40  are integrated by a casing  41  as an assembly which form a battery group. The group of the batteries  40  is placed in such a manner that its front portion has a larger width than its rear portion in the vehicle width direction (rightward and leftward direction). This makes it possible to prevent an increase in the vertical dimension of the whole of the batteries  40 , while increasing the capacity of the whole of the batteries  40 . Correspondingly, each of the middle case  21  and the upper case  22  is configured in such a manner that its front portion has a larger width than its rear portion. This allows the driver seated on the seat  30  to easily grip the battery case  20  with their legs. 
         [0040]    The rear region of the region of the middle case  21 , which is surrounded by the frame member  32 , is closed by a bottom plate  33  made of metal, which is fastened to the frame member  32  by welding, while the front region of the region of the middle case  21 , which is surrounded by the frame member  32 , forms an opening  32   c  which is in communication with the inner space of the lower case  23 . In the interior of the middle case  21  and the upper case  22 , the plurality of batteries  40  are accommodated and placed on the frame member  32  and the bottom plate  33 . The batteries  40  are also accommodated in the interior of the lower case  2 . In other words, the middle case  21  and the upper case  22  constitute an upper battery accommodating section, while the lower case  23  constitutes a lower battery accommodating section. The lower case  23  as the lower battery accommodating section is shorter in length in the forward and rearward direction than the middle case  21  and the upper case  22  as the upper battery accommodating section, and is connected to the front lower portion of the middle case  21 . The motor unit  25  is placed immediately behind the lower case  23  and immediately below the middle case  21 . 
         [0041]    In other words, the electric motor  42  is placed below the battery case. In the present embodiment, more specifically, the electric motor  42  is placed below the rear portion of the battery case  20  and rearward relative to the front portion of the battery case  20 . The front portion of the battery case  20  protrudes downward. The upper surface of the electric motor  42  is placed above the lowermost surface of the battery case  20 . The front surface of the electric motor  42  is placed forward relative to the rearmost surface of the battery case  20 . This allows the batteries  40  and the electric motor  42  to be close to each other, and the lower end of the battery case  20  to be located as low as possible. The terminal block of the electric motor  42  is placed below the upper surface of the batteries  40 , and at least a portion of an electric wire connecting the inverter  47  to the electric motor  42  runs through the interior of the battery case  20 . 
         [0042]    The upper surface of the upper case  22  of the battery case  20  is formed with an electric component region  22   a  surrounded by a peripheral rib  22   e . The electric component cover  26  is placed over the upper surface of the upper case  22  along the peripheral rib  22   e , thereby forming an electric component space S 1 . The electric component cover  26  is formed with a recess  26   a  corresponding to a recess  28   d  of the upper cover  28 . In the electric component space S 1 , the electric component group  46  is placed. In other words, the electric component group  46  is placed above the batteries  40  to overlap with the batteries  40  when viewed from above. The electric component group  46  includes electric components associated with a high-voltage current of the batteries  40 , through which the high-voltage current flows. For example, the electric component group  46  includes at least one of the inverter  47  (switching device), the DC/DC converter  50  (transformer), a ground leakage sensor  51 , a DC/DC converter relay  52 , a varistor  53 , a discharging relay  55 , a charging relay  57 , a fuse  59 , a precharge resistor  60 , and a service plug  71 . In the present example, the electric component group  46  includes all of the inverter  47 , the DC/DC converter  50 , the ground leakage sensor  51 , the DC/DC converter relay  52 , the varistor  53 , the discharging relay  55 , the charging relay  57 , the fuse  59 , the precharge resistor  60 , and the service plug  71 . Further, the electric component group  46  may include electric components associated with a low-voltage current. In the present example, the electric component group  46  includes a fan  48  and the ECU  54  (control device). Between the motor unit  25  and the inverter  47 , oil as a cooling medium is circulated via cooling medium pipes  64 ,  65 , the oil pump  45 , an oil cooler  69 , etc., to cool the inverter  47  and the electric motor  43 . 
         [0043]    The upper case  22  of the battery case  20  is provided with a seat section  22   c  protruding upward from the upper surface thereof, in a location that is rearward relative to the electric component cover  26 . The charging connector  75  is mounted on the seat section  22   c , to charge the batteries  40  with the electric power supplied externally. More specifically, the charging connector  75  is integrated with the battery case  20  outside of the battery case  20  to constitute a portion of the power unit  19 . The charging connector  75  is placed above the batteries  40  to overlap with the batteries  40  when viewed from above. The rear wall portion of the electric component cover  26  is formed with an insertion hole  26   c . The electric wire extending from the charging connector  75  is guided to the electric component space S 1  through the insertion hole  26   c . The charging connector  75  is provided with a connector connection surface  76  to which a power supply connector  90  of an L-shape connected to an outside power supply via a cable  91  is connected. The connector connection surface  76  faces a vehicle width direction (in the present example, leftward). The connector connection surface  76  is provided with a quick charging connector  77  and a normal charging connector  78 . The quick charging connector  77  and the normal charging connector  78  are arranged at upper and lower sides, respectively. 
         [0044]    As shown in  FIGS. 5 and 7 , the fan  48  is mounted to the center portion of the electric component region  22   a  provided in the upper surface of the upper case  22  of the battery case  20 . The upper wall of the upper case  22  is formed with an air inlet  22   g  via which the electric component space S 1  is in communication with the battery space S 2 . The fan  48  causes the air to flow from the interior of the electric component space S 1  into the battery space S 2  through the air inlet  22   g . The upper case  22  is formed with a duct member  22   f  defining an air passage connecting the discharge outlet of the fan  48  to the air inlet  22   g.    
         [0045]    As shown in  FIG. 5 , in the battery space S 2  in the interior of the battery case  20 , the batteries  40  are placed to be spaced from each other in the forward and rearward direction, to form a cooling passage C 1  extending vertically, immediately below the air inlet  22   g . The batteries  40  are integrated as an assembly by the casing  41 . A space formed between the batteries  40  extends in the direction in which the air flows into the battery space S 2 , at a location where the air flows into the battery space S 2  through the air inlet  22   g . This space is made larger than the other spaces formed between the batteries  40 . This space is used as the cooling passage C 1 . In addition, a space is formed between the batteries  40  and the battery case  20  and used as a cooling passage C 2 . 
         [0046]    As shown in  FIG. 7 , in a region of the electric component region  22 , the pair of discharging relays  55 ,  56  are mounted on a current supply path connecting the batteries  40  to the inverter  47 , and the pair of charging relays  57 ,  58  are mounted on a current supply path connecting the charging connector  75  to the batteries  40 . In another region of the electric component region  22 , the fuse  59  provided in a power supply circuit and the precharge resistor  60  are mounted. From the electric component region  22 , a plurality of support elements  22   d  on which the inverter  47  is to be mounted protrude upward. The electric component region  22  is provided with a pair of bus bars  81  which are electric wires (power lines) protruding upward and electrically connected to the batteries  40  via the discharging relays  55 ,  56 , the fuse  59 , the precharge resistor  60 , and the like. A first bus bar module  80  (see  FIG. 8 ) protrudes upward from the battery space S 2  through an opening  22   b  formed in the electric component region  22 . The first bus bar module  80  includes three bus bars  94  to  96  (see  FIG. 9 ) stacked together, insulatively bonded together and integrated, which are electric wires used to supply a three-phase AC current from the inverter  47  to the electric motor  42 . Thus, the bus bar  80  can be easily handled, and generation of noise can be suppressed. 
         [0047]    As shown in  FIG. 6 , the inverter  47  is mounted on the support elements  22   d . The inverter  47  is placed above the upper case  22  to form a slight gap with the upper surface of the upper case  22 , and fastened to the battery case  20 . Since heat generated in the inverter  47  travels upward, it becomes possible to prevent heat generated in the inverter  47  from being transferred to the batteries  40 . Because of the vertical gap formed between the inverter  47  and the battery case  20 , heat transfer to the batteries  40  can be prevented more effectively. The inverter  47  is configured to convert the DC power supplied from the batteries  40  (see  FIG. 3 ) into AC power and supply the AC power to the electric motor  42  (see  FIG. 3 ), and includes a semiconductor switching element. The inverter  47  is placed above the batteries  40  to overlap with the battery case  20  when viewed from above. The inverter  47  is placed above the battery case  20  to be included within the battery case  20  when viewed from above. The inverter  47  has a flat shape in which a vertical dimension is smaller than a dimension in the forward and rearward direction and a dimension in the rightward and leftward direction. The inverter  47  is placed inward relative to the front and rear edges and right and left edges of the assembly of the battery case  20  and the batteries  40  when viewed from above. 
         [0048]    The inverter  47  is placed above the fan  48 , the discharging relays  55 ,  56 , and the charging relays  57 ,  58  to overlap with the fan  48 , the discharging relays  55 ,  56 , and the charging relays  57 ,  58  when viewed from above. In other words, the fan  48 , the discharging relays  55 ,  56 , and the charging relays  57 ,  58  are placed between the battery case  20  and the inverter  47 . In this structure, many electric components can be placed in the electric component region  22   a  with a small area, and the electric wires or the like connecting them to each other, and the electric wires or the like connecting them to the batteries  40 , can be reduced in length. 
         [0049]    As shown in  FIG. 5 , an electromagnetic shield member  49  formed by bending a metal plate is placed over the inverter  47 . The electromagnetic shield member  49  is electrically grounded at a ground potential equal to that of the electric components in a weak electric system. The electromagnetic shield member  49  has a step shape and is placed on the inverter  47  to correspond to the support elements  22   d . The electromagnetic shield member  49  supports a plurality of electric components. On the upper surface of the electromagnetic shield member  49  with a step shape, for example, the ECU  54  for controlling the ground leakage sensor  51 , the DC/DC converter relay  52 , the varistor  53 , the inverter  47 , the relays  52 ,  55  to  58 , etc., are mounted. On the lower surface of the electromagnetic shield member  49 , the DC/DC converter  50  is mounted such that the DC/DC converter  50  forms a gap with the inverter  47 . In other words, the electromagnetic shield member  49  is interposed between the DC/DC converter  50  and the ECU  54  to isolate them from each other. In this structure, the electromagnetic shield member  49  shields electromagnetic noise generated from the DC/DC converter  50  and the inverter  47  and thereby prevents the noise from being transmitted to the ECU  54 . In other words, since the electric components in the weak electric system (the ECU, the sensors, etc.) are placed above the electric components in the strong electric system (the inverter, the DC/DC converter, etc.) with the metal plate interposed between the electric components in the weak electric system and the electric components in the strong electric system, space-saving can be achieved while preventing influence of the electromagnetic noise on the electric components in the weak electric system. As defined herein, a voltage equal to the voltage (e.g., 200V) of the batteries  40  connected in series is to be applied to the electric components in the strong electric system, while a voltage (e.g., 12V) lower than the voltage of the battery group  40  is to be applied to the electric components in the weak electric system, which, for example, input, output and/or calculate control signals, etc. 
         [0050]    The electric component group  46  placed above the battery case  20  is configured such that the electric components are placed in a plurality of layers and arranged vertically to overlap with each other when viewed from above. In the present embodiment, the inverter  47  is placed above the fan  48 , the discharging relays  55 ,  56  and the charging relays  57 ,  58 , to overlap with the fan  48 , the discharging relays  55 ,  56  and the charging relays  57 ,  58 , when viewed from above, the DC/DC converter  50  is placed above the inverter  47  to overlap with the inverter  47  when viewed from above, the ECU  54  is placed above the DC/DC converter  50  to overlap with the DC/DC converter  50 , when viewed from above, the ground leakage sensor  51 , the DC/DC converter relay  52 , and the varistor  53  are placed above the inverter  47  to overlap with the inverter  47  when viewed from above, and laterally relative to the ECU  54 . 
         [0051]      FIG. 8  is a perspective view of major components for explaining bus bar modules  80 ,  82  to  85  in the interior of the battery case  20  of the electric motorcycle  1  of  FIG. 1 . As shown in  FIGS. 1 ,  3 ,  6 , and  8 , the first bus bar module  80  as a portion of the electric wire (power line) connecting the electric motor  42  (see  FIG. 1 ) to the inverter  47  vertically runs through the interior space of the battery case  20  (see  FIG. 4 ). Terminal sections  80   b  at the lower end portion of the first bus bar module  80  are placed in a terminal accommodating section  23   b  (terminal box) of the lower case  23 . Between the terminal sections  80   b  in the terminal accommodating section  23   b  and the terminal section (not shown) of the electric motor  42  accommodated in the terminal block  44   b  of the motor unit  25 , the three high-voltage electric cables  27  (see  FIG. 1 ) are placed to couple the terminal sections in a location outside of the battery case  20 . In this case, since the lower case  23  including the terminal accommodating section  23   b  and the electric motor  42  are adjacent to each other in the forward and rearward direction, the high-voltage electric cables  27  exposed to the outside can be reduced in length. Thus, the electric wire connecting the inverter  47  to the electric motor  42  includes the first bus bar module  80  and the electric cables  27 , and a portion of the first bus bar module  80  constitutes a running portion vertically running through the interior space of the battery case  20 . 
         [0052]    As shown in  FIG. 1 , the electric cables  27  are located between the seat  30  and the batteries  40  and spaced apart from the seat  30 . More specifically, the seat  30  is placed above and rearward relative to the battery case  20 , while the terminal accommodating section  23   b  of the battery case  20  to which one end portions of the electric cables  27  are connected is placed on the front lower portion of the battery case  20 . The terminal block  44   b  provided on the casing  44  of the electric motor  42  is placed to face downward. 
         [0053]      FIG. 9  is a perspective view of the first bus bar module  80  of  FIG. 8 . As shown in  FIGS. 8 and 9 , the first bus bar module  80  includes the three bus bars  94  to  96  for a three-phase AC current which are stacked together, insulatively bonded together, and preliminarily integrated. The end portions of the three bus bars  94  to  96  are bent such that their terminal ends are at different positions. The terminal sections  80   a  of the first bus bar module  80  which are closer to the inverter  47  are aligned, while the terminal sections  80   b  of the first bus bar module  80  which are closer to electric motor  25  are aligned. The direction in which the terminal sections  80   a  are aligned and the direction in which the terminal sections  80   b  are aligned are different and orthogonal to each other. The vertically extending portions of the three bus bars  94  to  96  are stacked in the direction (forward and rearward direction) in which the terminal sections  80   b  are aligned. In the straddle-type vehicle, the dimension of the vehicle body in the rightward and leftward direction is small. In view of this, at least either the terminal sections  80   a  or the terminal sections  80   b  of the first bus bar module  80  are preferably aligned in the forward and rearward direction. 
         [0054]    The upper portion of the first bus bar module  80  which is provided with the three terminal sections  80   a  protrudes upward from the battery case  20 , and the terminal sections  80   a  are connected to the output terminal of the inverter  47 . The first bus bar module  80  runs through the space (cooling passage C 1 ) formed between the battery  40  on a first row from a front and the battery  40  on a second row from the front, among the batteries  40  arranged in three rows in the forward and rearward direction. In other words, the first bus bar module  80  is placed in the front portion of the assembly of the batteries  40 . Since the first bus bar module  80  as the electric wire connecting the inverter  47  to the electric motor  42  runs through the interior (i.e., cooling passage C 1 ) of the assembly of the batteries  40 , the first bus bar module  80  can be protected, as compared to a case where the first bus bar module  80  is placed between the battery case  20  and the batteries  40 . In the present embodiment, the first bus bar module  80  runs through the space formed between the batteries  40  aligned in the forward and rearward direction, and through the space that is inward relative to the right and left ends of the assembly of the batteries  40  in the rightward and leftward direction. Therefore, the first bus bar module  80  can be protected suitably. 
         [0055]    Since the battery case  20  is provided with the terminal accommodating section  23   b  (terminal box) for electrically connecting the first bus bar module  80  to the electric cables  27  (see  FIG. 1 ), an assembling operation can be performed more easily, than in a case where the first bus bar module  80  is directly connected to the electric cables  27 . Specifically, the terminal accommodating section  23   b  accommodates an electric conductor  93  including bus bar terminal sections  93   a  connected to the terminal sections  80   b  of the first bus bar module  80  and cable terminal sections  93   b  connected to the electric cables  27  (see  FIG. 1 ). The bus bar terminal sections  93   a  lead inward of the battery case  20 , while the cable terminal sections  93   b  lead outward of the battery case  20 . 
         [0056]    The terminal accommodating section  23   b  is located inward relative to the front, rear, right, and left outer edges of the battery case  20  when viewed from above. In this structure, for example, when the vehicle body falls, a portion of the battery case  20  which is other than the terminal accommodating section  23   b  collides with an obstacle first, and as a result, the terminal accommodating section  23   b  is protected. Also, the terminal accommodating section  23   b  is located above the lowermost end of the group of the batteries  40 . Therefore, when the vehicle body falls, the lowermost end of the battery case  20  collides with an obstacle before the terminal accommodating section  23   b  collides with the obstacle, and as a result, the terminal accommodating section  23   b  is protected. 
         [0057]      FIG. 10  is a perspective view of a second bus bar module  98  of  FIG. 8 . As shown in  FIGS. 8 and 10 , the plurality of bus bars  82 ,  83  connecting the batteries  40  accommodated in the lower case  23  to the batteries  40  accommodated in the middle case  21  (see  FIG. 3 ) are configured such that the surfaces of intermediate portions  82   a ,  83   a  thereof are joined to each other via an insulating material, and thereby the second bus bar module  98  is integrated. In this structure, a virtual line connecting one end portion of the bus bar  82  to the other end portion of the bus bar  82  and a virtual line connecting one end portion of the bus bar  83  to the other end portion of the bus bar  83  do not cross each other. Therefore, the bus bars  82 ,  83  are bent to allow the intermediate portions  82   a ,  83   a  to contact each other. 
         [0058]      FIG. 11  is a perspective view of a third bus bar module  99  of  FIG. 8 . As shown in  FIGS. 8 and 11 , bus bars  84  to  89  for directly connecting the batteries  40  to each other are placed in a space formed between the group of the batteries  40  and the upper wall (upper wall of the upper case  22 ) of the battery case  20  (see  FIG. 5 ). The plurality of bus bars  84  to  89 , are configured such that the surfaces of intermediate portions thereof close to each other are joined to each other via an insulating material, to form the third bus bar module  99 . 
         [0059]    The batteries  40  accommodated in the battery case  20  are electrically interconnected in series, via the bus bars  82  to  89  of the second bus bar module  98  and the third bus bar module  99 . The positive terminal and negative terminal at the terminal ends of the group of the batteries  40  connected in series are connected to the bus bars  81  (see  FIG. 7 ) provided in the electric component space to be connected to the inverter  47 . 
         [0060]    As described above, the first to third bus bar modules  80 ,  98 ,  99  are a plurality of sub-assemblies each of which includes a plurality of bus bars which are integrated. Therefore, the many bus bars  82  to  89 ,  94  to  96  are mounted more efficiently. 
         [0061]    The first bus bar module  80  and the second bus bar module  98  run through the cooling passages C 1 , C 2  (see  FIG. 5 ), in the battery space S 2  in the interior of the battery case  20 . In other words, the cooling passages C 1 , C 2  with a relatively large dimension to cool the batteries  40  are used as the accommodating space in which the bus bars  82 ,  83 ,  94  to  96  are accommodated. The air blown by the fan  48  is introduced into the battery case  20  through the air inlet  22   g , takes heat out of the batteries  40  and the bus bars  82 ,  83 ,  94  to  96  while flowing through the cooling passages C 1 , C 2 , and is thereafter discharged to outside of the battery case  20  through an air outlet (not shown) provided on the battery case  20 . 
         [0062]    In accordance with the above-described configuration, since the electric wire (first bus bar module  80 ) connecting the inverter  47  to the electric motor  42  runs through the interior space of the battery case  20 , this electric wire can be easily protected from the outside and the space efficiency can be increased. In addition, since the electric wire which is the first bus bar module  80  can be covered by the battery case  20 , the external appearance of the electric vehicle can be improved. Furthermore, since the battery case  20  is interposed between the electric motor  42  and the inverter  47  in the vertical direction, a distance from the batteries  40  to the inverter  47  and a distance from the batteries  40  to the electric motor  42  can be reduced, and the first bus bar module  80  which is the electric wire connecting the inverter  47  to the electric motor  42  is allowed to run through the interior of the battery case  20 , which can reduce the length of the first bus bar module  80 . Moreover, since the inverter  47  is adjacent to the battery case  20 , the electric wire extending to outside of the battery case  20  can be reduced. 
         [0063]    The electric wire connecting the inverter  47  to the electric motor  42  includes the first bus bar module  80 , as the running portion vertically running through the internal space of the battery case  20 , and the three electric cables  27  for a three-phase AC current connecting the first bus bar module  80  to the electric motor  42  are provided between the lower portion of the battery case  20  and the casing  44  of the electric motor  42  to couple the battery case  20  and the electric motor  42  to each other. In this configuration, even when the inverter  47  and the electric motor  42  are placed to be vertically spaced apart from each other with the battery case  20  interposed between the inverter  47  and the electric motor  42 , the three high-voltage electric cables  27  which have a large cross-sectional area and are not easily bent can be reduced in length and a wiring operation can be easily performed, as compared to a case where the electric wire connecting the inverter  47  to the electric motor  42  runs through a region outside of the case  20 . 
         [0064]    Since the three bus bars  94  to  96  for a three-phase AC current constitute the first bus bar module  80  by joining together their surfaces via the insulating material, the three bus bars  94  to  96  for a three-phase AC current can be accommodated in a compact manner in the limited space S 2  in the interior of the battery case  20 , and can be handled more easily during assembly. In addition, since the three bus bars  94  to  96  for a three-phase AC current are joined to each other via the insulating material, it becomes possible to prevent a situation in which a noise generated in one of the bus bars  94  to  96  affects the remaining bus bars of the bus bars  94  to  96 . 
         [0065]    The first bus bar module  80  includes a portion extending through the interior of the battery case  20  and through the opening  22   b  on the upper surface of the battery case  20 , and protruding upward. This portion is connected to the inverter  47  placed on the upper portion of the battery case  20 . Therefore, the electric components such as the inverter  47  can be mounted later to the upper portion of the battery case  20  which is closed. The first to third bus bar modules  80 ,  98 ,  99  run through the cooling passages C 1 , C 2  in the battery space S 2  in the interior of the battery case  20 . In this configuration, the space reserved to cool the batteries  40  is used as the space reserved to allow the electric wires (bus bars) to run therethrough, and as a result, the size of the battery case  20  is not increased. The air flowing through the cooling passages C 1 , C 2  takes heat out of the first to third bus bar modules  80 ,  98 ,  99 , as well as the batteries  40 , and thereby an increase in the electric resistances in the first to third bus bar modules  80 ,  98 ,  99  can be suppressed. 
         [0066]    The terminal block of the inverter  47  and the terminal block of the electric motor  42  are placed inward relative to the front, rear, right, and left edges of the assembly of the batteries  40  and of the battery case  20 . Therefore, the electric wires can be placed inward relative to the contour of the battery case  20 , when viewed from above, to electrically connect the inverter  47  to the electric motor  42 . Since the electric component group  46  is placed outside of the battery case  20 , maintenance for the electric component group  46  can be performed more easily without a need to open the battery case  20 . 
         [0067]    Since the electric component group  46  including the inverter  47  is placed on the upper case  22  detachably mounted to the middle case  21  of the battery case  20 , assembly of the power unit  19  can be carried out more easily in a state in which the electric components are mounted to the upper case  22  as a sub-assembly. When the battery case  20  is detached from the vehicle body, the electric component group  46  can be detached from the vehicle body together with the batteries  40 . This allows an operator to easily check the operation of the batteries  40  in the state in which the batteries  40  are detached from the vehicle body before or after shipping. 
         [0068]    Since the electric component group  46  is placed above the batteries  40 , assembly of the electric component group  46  can be carried out more easily than in a case where the electric components are placed below the batteries  40 . Since the electric component group  46  including the inverter  47  is placed on the upper case  22  detachably mounted to the middle case  21  of the battery case  20 , assembly can be carried out more easily in a state in which the electric component group  46  is mounted to the battery case  20  as a sub-assembly. When the battery case  20  is detached from the vehicle body, the electric component group  46  can be detached from the vehicle body together with the batteries  40 . This allows the operator to easily check the operation of the batteries  40  and the like, in the state in which the batteries  40  are detached from the vehicle body before or after shipping. 
         [0069]    The electric cables  27  are placed on the same side (in the present example, left side) with respect to the vehicle body as the side where the side stand  17  is placed. Therefore, when the side stand  17  is placed in the use position and the vehicle body is made to independently stand in the inclined state, the electric cables  27  are not seen easily and thereby the external appearance of the electric vehicle can be improved. Since the middle case  21  is made of metal, the electric wires in the interior of the battery case  20  can be suitably protected, and leakage of electromagnetic noise radiated from the bus bar modules  80 ,  98 ,  99  to outside of the battery case  20  can be suppressed. Since the electric cables  27  which are a portion of the electric wire connecting the inverter  47  to the electric motor  42  are short in length, a cover for covering the electric cables  27  can be reduced in size. 
         [0070]    Since the electric cables  27  are positioned apart from the seat  30  with the batteries  40  located between the electric cables  27  and the seat  30 , it becomes possible to prevent a situation in which the electric cables  27  are present near the driver and interfere with the lower body of the driver such as their legs or their feet. This allows the driver more flexibility as to their driving posture. The rear portion of the battery case  20  is smaller in dimension in the rightward and leftward direction than the front portion of the battery case  20  is, and the electric wires (first bus bar module  80  and the electric cables  27 ) connecting the inverter  47  to the electric motor  42  are placed in the front portion of the group of the batteries  40 . Therefore, the electric wires can be laid out more flexibly while allowing the driver to easily grip the battery case  20  with their knees. 
         [0071]    Although in the present embodiment, the electric motorcycle has been exemplarily described as the electric vehicle, the electric vehicle may be a vehicle including three or more wheels, for example an ATV (all-terrain vehicle) so long as the vehicle is a straddle-type vehicle. Although the bus bars have been exemplarily described as the electric wires running through the interior of the battery case  20 , other electric wires (e.g., electric cables) may be used. Or, a part or the entirety of the electric component group  46  including the inverter  47  may be placed inside of the battery case  20 . Or, the cooling medium pipes  64 ,  65  may run through a region outside of the battery case  20 , instead of the interior of the battery case  20 . The present invention is not limited to the above-described embodiment, and its configuration can be changed, added to, or deleted from within the scope of the invention. 
       INDUSTRIAL APPLICABILITY 
       [0072]    As described above, an electric vehicle of the present invention has the above-described advantages, and is effectively applicable to an electric vehicle such as an electric motorcycle, which can obtain these advantages. 
       REFERENCE CHARACTER LIST 
       [0000]    
       
         
           
               1  electric motorcycle (electric vehicle) 
               20  battery case 
               27  electric cable 
               40  battery 
               42  electric motor 
               44  casing (motor case) 
               46  electric component group 
               47  inverter 
               80 ,  98 ,  99  bus bar module 
               81 ,  82  to  89 ,  94  to  96  bus bar 
             C 1 , C 2  cooling passage 
             S 2  battery space