Electric vehicle

An electric vehicle includes an electric motor which generates a driving power for driving a wheel, a battery storing DC power to be supplied to the electric motor, a battery case accommodating the battery 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. The electric wire runs through an internal space of the battery case, and may penetrate an upper surface of the battery case, protrude upward, and connect to an inverter placed on an upper portion of the battery case. The electric wire may run through a cooling passage in the internal space. The electric wire may be interposed between the electric motor and the inverter. The electric wire may run vertically through the internal space.

TECHNICAL FIELD

The present invention relates to an electric vehicle which drives a wheel with driving power generated in an electric motor.

BACKGROUND ART

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

SUMMARY OF INVENTION

Technical Problem

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.

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

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 into AC power and supplies the AC 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.

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.

The battery case may be placed between the electric motor and the inverter.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the embodiment will be described with reference to the drawings.

FIG. 1is a left side view of an electric motorcycle1according to the embodiment of the present invention.FIG. 2is a right side view of a power unit19of the electric motorcycle1ofFIG. 1. As shown inFIGS. 1 and 2, the electric motorcycle1which is a straddle-type electric vehicle includes a front wheel2which is a driven wheel, and a rear wheel3which is a drive wheel. The front wheel2is rotatably mounted to the lower end portion of a front fork4. The upper portion of the front fork4is integrated with a steering shaft (not shown). The steering shaft is rotatably supported by a head pipe5of a vehicle body in a state in which the steering shaft is inserted into the head pipe5. A bar-type handle6extending 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 handle6.

The vehicle body frame10of the electric motorcycle1includes a pair of right and left main frames11extending rearward from the head pipe5such that they are inclined slightly downward. A pair of right and left down frames14are coupled to the front end portions of the main frames11, respectively such that the down frames14extend downward therefrom, and then rearward. The rear end portions of the main frames11are connected to the upper portion of a pivot frame12of a frame shape. The front end portion of a swing arm15is mounted to the pivot frame12such that the swing arm15supports the rear wheel3and is vertically pivotable. A rear frame13is placed above the swing arm15and is connected to the rear end portions of the main frames11. A side stand17is placed at the left side of the pivot frame12. The side stand17can be tilted between a use position and a non-use position. In the use position, the side stand17supports the vehicle body of the electric motorcycle1such that the vehicle body is inclined to the right or to the left (in the present example, to the left).

The vehicle body frame10supports the power unit19in a space formed between the head pipe5and the pivot frame12. The power unit19includes a plurality of batteries40, an electric motor42, an inverter47(seeFIG. 2), and others which are integrated. The plurality of batteries40are accommodated into a battery case20. The battery case20includes a middle case21which 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 case22which is made of a resin and attached to the middle case21to close an upper opening in the middle case21, and a lower case23which is made of a resin and attached to the middle case21to close a lower opening in the front section of the middle case21.

A motor unit25is mounted to the battery case20in a location that is rearward relative to the lower case23and below the middle case21. Specifically, the motor unit25is fastened to a frame member32of the middle case21and the pivot frame12by brackets36,37. The motor unit25includes a casing44(motor case), the electric motor42accommodated in the casing44to generate driving power for moving the vehicle body, a transmission43accommodated in the casing44to change the speed of a rotational driving power output from the electric motor42, an oil pan44aattached to the lower portion of the casing44, and an oil pump45which suctions up and discharges oil stored in the oil pan44a. The rotational driving power output from the transmission43is transmitted to the rear wheel3via a chain16.

An electric component cover26is attached to the upper surface of the battery case20to form an electric component space accommodating an electric component group46, together with the upper case22. The electric component cover26is insulative, and is made of, for example, an insulating resin material. The electric component cover26is covered by an upper cover28which is a dummy tank which looks like a fuel tank of a conventional engine-driven motorcycle. The upper cover28is made of, for example, a metal material. The electric component cover26is lower in strength than the upper cover28is. The rear portion of the upper cover28is formed with a connector opening28athrough which a charging connector75(seeFIG. 5), which will be described later, is exposed. The connector opening28is closed by a connector lid member29. The rear portion of the upper cover28, corresponding to the connector lid member29, is smaller in dimension in a vehicle width direction than the center portion of upper cover28, covering the electric component cover26. A driver seat30supported by the rear frame13is placed rearward relative to the upper cover28. The driver seated on the seat30can grip the upper cover28with their legs. The upper surface of the battery case20is located below the upper end of the seat30. In this configuration, even when the electric component group46including the inverter47and the like is placed on the battery case20, it becomes possible to lessen the amount of the electric component group46which protrudes upward from a virtual line connecting the seat30to the head pipe5.

The batteries40are placed between the head pipe5and the seat30. At least a portion of the batteries40is placed above and forward relative to footrests of the vehicle body, and between the legs of the driver seated on the seat30. The electric motor42is placed between the head pipe5and the seat30. The electric motor42is supported on the pivot frame12and is configured not to be pivoted together with the swing arm15. The battery case20is positioned between the electric motor42and the inverter47.

The casing44of the motor unit25is placed inward relative to the peripheral edge of the bottom surface of the battery case20when viewed from above, and the inverter47is placed inward relative to the peripheral edge of the upper surface of the battery case20when viewed from above. This makes it possible to prevent electric cables27connecting the inverter47to the electric motor42from protruding in the forward and rearward direction and the rightward and leftward direction of the battery case20.

FIG. 3is an exploded perspective view of the power unit19(the motor unit25is not shown) of the electric motorcycle1ofFIG. 1, when viewed from the left and front.FIG. 4is an exploded perspective view of the power unit19(the motor unit25is not shown) of the electric motorcycle1ofFIG. 1, when viewed from the right and rear.FIG. 5is a longitudinal sectional view of the power unit19(motor unit25is not shown) of the electric motorcycle1ofFIG. 1, when viewed from the left.FIG. 6is a perspective view showing a state in which an ECU54, a DC/DC converter50, and the like in the region above the battery case20of the electric motorcycle ofFIG. 1are detached.FIG. 7is a perspective view showing a state in which the inverter47and the like in the region above the battery case20ofFIG. 6are further detached.

As shown inFIGS. 2 to 5, the plurality of batteries40storing a DC power to be supplied to the electric motor42are aligned in a battery space S2in the interior of the battery case20. The plurality of batteries40are integrated by a casing41as an assembly which form a battery group. The group of the batteries40is 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 batteries40, while increasing the capacity of the whole of the batteries40. Correspondingly, each of the middle case21and the upper case22is configured in such a manner that its front portion has a larger width than its rear portion. This allows the driver seated on the seat30to easily grip the battery case20with their legs.

The rear region of the region of the middle case21, which is surrounded by the frame member32, is closed by a bottom plate33made of metal, which is fastened to the frame member32by welding, while the front region of the region of the middle case21, which is surrounded by the frame member32, forms an opening32cwhich is in communication with the inner space of the lower case23. In the interior of the middle case21and the upper case22, the plurality of batteries40are accommodated and placed on the frame member32and the bottom plate33. The batteries40are also accommodated in the interior of the lower case23. In other words, the middle case21and the upper case22constitute an upper battery accommodating section, while the lower case23constitutes a lower battery accommodating section. The lower case23as the lower battery accommodating section is shorter in length in the forward and rearward direction than the middle case21and the upper case22as the upper battery accommodating section, and is connected to the front lower portion of the middle case21. The motor unit25is placed immediately behind the lower case23and immediately below the middle case21.

In other words, the electric motor42is placed below the battery case. In the present embodiment, more specifically, the electric motor42is placed below the rear portion of the battery case20and rearward relative to the front portion of the battery case20. The front portion of the battery case20protrudes downward. The upper surface of the electric motor42is placed above the lowermost surface of the battery case20. The front surface of the electric motor42is placed forward relative to the rearmost surface of the battery case20. This allows the batteries40and the electric motor42to be close to each other, and the lower end of the battery case20to be located as low as possible. The terminal block of the electric motor42is placed below the upper surface of the batteries40, and at least a portion of an electric wire connecting the inverter47to the electric motor42runs through the interior of the battery case20.

The upper surface of the upper case22of the battery case20is formed with an electric component region22asurrounded by a peripheral rib22e. The electric component cover26is placed over the upper surface of the upper case22along the peripheral rib22e, thereby forming an electric component space S1. The electric component cover26is formed with a recess26acorresponding to a recess28dof the upper cover28. In the electric component space S1, the electric component group46is placed. In other words, the electric component group46is placed above the batteries40to overlap with the batteries40when viewed from above. The electric component group46includes electric components associated with a high-voltage current of the batteries40, through which the high-voltage current flows. For example, the electric component group46includes at least one of the inverter47(switching device), the DC/DC converter50(transformer), a ground leakage sensor51, a DC/DC converter relay52, a varistor53, a discharging relay55, a charging relay57, a fuse59, a precharge resistor60, and a service plug71. In the present example, the electric component group46includes all of the inverter47, the DC/DC converter50, the ground leakage sensor51, the DC/DC converter relay52, the varistor53, the discharging relay55, the charging relay57, the fuse59, the precharge resistor60, and the service plug71. Further, the electric component group46may include electric components associated with a low-voltage current. In the present example, the electric component group46includes a fan48and the ECU54(control device). Between the motor unit25and the inverter47, oil as a cooling medium is circulated via cooling medium pipes64,65, the oil pump45, an oil cooler69, etc., to cool the inverter47and the electric motor42.

The upper case22of the battery case20is provided with a seat section22cprotruding upward from the upper surface thereof, in a location that is rearward relative to the electric component cover26. The charging connector75is mounted on the seat section22c, to charge the batteries40with the electric power supplied externally. More specifically, the charging connector75is integrated with the battery case20outside of the battery case20to constitute a portion of the power unit19. The charging connector75is placed above the batteries40to overlap with the batteries40when viewed from above. The rear wall portion of the electric component cover26is formed with an insertion hole26c. The electric wire extending from the charging connector75is guided to the electric component space S1through the insertion hole26c. The charging connector75is provided with a connector connection surface76to which a power supply connector90of an L-shape connected to an outside power supply via a cable91is connected. The connector connection surface76faces a vehicle width direction (in the present example, leftward). The connector connection surface76is provided with a quick charging connector77and a normal charging connector78. The quick charging connector77and the normal charging connector78are arranged at upper and lower sides, respectively.

As shown inFIGS. 5 and 7, the fan48is mounted to the center portion of the electric component region22aprovided in the upper surface of the upper case22of the battery case20. The upper wall of the upper case22is formed with an air inlet22gvia which the electric component space S1is in communication with the battery space S2. The fan48causes the air to flow from the interior of the electric component space S1into the battery space S2through the air inlet22g. The upper case22is formed with a duct member22fdefining an air passage connecting the discharge outlet of the fan48to the air inlet22g.

As shown inFIG. 5, in the battery space S2in the interior of the battery case20, the batteries40are placed to be spaced from each other in the forward and rearward direction, to form a cooling passage C1extending vertically, immediately below the air inlet22g. The batteries40are integrated as an assembly by the casing41. A space formed between the batteries40extends in the direction in which the air flows into the battery space S2, at a location where the air flows into the battery space S2through the air inlet22g. This space is made larger than the other spaces formed between the batteries40. This space is used as the cooling passage C1. In addition, a space is formed between the batteries40and the battery case20and used as a cooling passage C2.

As shown inFIG. 7, in a region of the electric component region22a, the pair of discharging relays55,56are mounted on a current supply path connecting the batteries40to the inverter47, and the pair of charging relays57,58are mounted on a current supply path connecting the charging connector75to the batteries40. In another region of the electric component region22, the fuse59provided in a power supply circuit and the precharge resistor60are mounted. From the electric component region22a, a plurality of support elements22don which the inverter47is to be mounted protrude upward. The electric component region22ais provided with a pair of bus bars81which are electric wires (power lines) protruding upward and electrically connected to the batteries40via the discharging relays55,56, the fuse59, the precharge resistor60, and the like. A first bus bar module80(seeFIG. 8) protrudes upward from the battery space S2through an opening22bformed in the electric component region22a. The first bus bar module80includes three bus bars94to96(seeFIG. 9) stacked together, insulatively bonded together and integrated, which are electric wires used to supply a three-phase AC current from the inverter47to the electric motor42. Thus, the bus bar module80can be easily handled, and generation of noise can be suppressed.

As shown inFIG. 6, the inverter47is mounted on the support elements22d. The inverter47is placed above the upper case22to form a slight gap with the upper surface of the upper case22, and fastened to the battery case20. Since heat generated in the inverter47travels upward, it becomes possible to prevent heat generated in the inverter47from being transferred to the batteries40. Because of the vertical gap formed between the inverter47and the battery case20, heat transfer to the batteries40can be prevented more effectively. The inverter47is configured to convert the DC power supplied from the batteries40(seeFIG. 3) into AC power and supply the AC power to the electric motor42(seeFIG. 3), and includes a semiconductor switching element. The inverter47is placed above the batteries40to overlap with the battery case20when viewed from above. The inverter47is placed above the battery case20to be included within the battery case20when viewed from above. The inverter47has 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 inverter47is placed inward relative to the front and rear edges and right and left edges of the assembly of the battery case20and the batteries40when viewed from above.

The inverter47is placed above the fan48, the discharging relays55,56, and the charging relays57,58to overlap with the fan48, the discharging relays55,56, and the charging relays57,58when viewed from above. In other words, the fan48, the discharging relays55,56, and the charging relays57,58are placed between the battery case20and the inverter47. In this structure, many electric components can be placed in the electric component region22awith 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 batteries40, can be reduced in length.

As shown inFIG. 5, an electromagnetic shield member49formed by bending a metal plate is placed over the inverter47. The electromagnetic shield member49is electrically grounded at a ground potential equal to that of the electric components in a weak electric system. The electromagnetic shield member49has a step shape and is placed on the inverter47to correspond to the support elements22d. The electromagnetic shield member49supports a plurality of electric components. On the upper surface of the electromagnetic shield member49with a step shape, for example, the ECU54for controlling the ground leakage sensor51, the DC/DC converter relay52, the varistor53, the inverter47, the relays52,55to58, etc., are mounted. On the lower surface of the electromagnetic shield member49, the DC/DC converter50is mounted such that the DC/DC converter50forms a gap with the inverter47. In other words, the electromagnetic shield member49is interposed between the DC/DC converter50and the ECU54to isolate them from each other. In this structure, the electromagnetic shield member49shields electromagnetic noise generated from the DC/DC converter50and the inverter47and thereby prevents the noise from being transmitted to the ECU54. 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 batteries40connected 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 group40is to be applied to the electric components in the weak electric system, which, for example, input, output and/or calculate control signals, etc.

The electric component group46placed above the battery case20is 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 inverter47is placed above the fan48, the discharging relays55,56and the charging relays57,58, to overlap with the fan48, the discharging relays55,56and the charging relays57,58, when viewed from above, the DC/DC converter50is placed above the inverter47to overlap with the inverter47when viewed from above, the ECU54is placed above the DC/DC converter50to overlap with the DC/DC converter50, when viewed from above, the ground leakage sensor51, the DC/DC converter relay52, and the varistor53are placed above the inverter47to overlap with the inverter47when viewed from above, and laterally relative to the ECU54.

FIG. 8is a perspective view of major components for explaining bus bar modules80, and bus bars82to85in the interior of the battery case20of the electric motorcycle1ofFIG. 1. As shown inFIGS. 1, 3, 6, and 8, the first bus bar module80as a portion of the electric wire (power line) connecting the electric motor42(seeFIG. 1) to the inverter47vertically runs through the interior space of the battery case20(seeFIG. 4). Terminal sections80bat the lower end portion of the first bus bar module80are placed in a terminal accommodating section23b(terminal box) of the lower case23. Between the terminal sections80bin the terminal accommodating section23band the terminal section (not shown) of the electric motor42accommodated in the terminal block44bof the motor unit25, the three high-voltage electric cables27(seeFIG. 1) are placed to couple the terminal sections in a location outside of the battery case20. In this case, since the lower case23including the terminal accommodating section23band the electric motor42are adjacent to each other in the forward and rearward direction, the high-voltage electric cables27exposed to the outside can be reduced in length. Thus, the electric wire connecting the inverter47to the electric motor42includes the first bus bar module80and the electric cables27, and a portion of the first bus bar module80constitutes a running portion vertically running through the interior space of the battery case20.

As shown inFIG. 1, the electric cables27are located between the seat30and the batteries40and spaced apart from the seat30. More specifically, the seat30is placed above and rearward relative to the battery case20, while the terminal accommodating section23bof the battery case20to which one end portions of the electric cables27are connected is placed on the front lower portion of the battery case20. The terminal block44bprovided on the casing44of the electric motor42is placed to face downward.

FIG. 9is a perspective view of the first bus bar module80ofFIG. 8. As shown inFIGS. 8 and 9, the first bus bar module80includes the three bus bars94to96for a three-phase AC current which are stacked together, insulatively bonded together, and preliminarily integrated. The end portions of the three bus bars94to96are bent such that their terminal ends are at different positions. The terminal sections80aof the first bus bar module80which are closer to the inverter47are aligned, while the terminal sections80bof the first bus bar module80which are closer to electric motor42are aligned. The direction in which the terminal sections80aare aligned and the direction in which the terminal sections80bare aligned are different and orthogonal to each other. The vertically extending portions of the three bus bars94to96are stacked in the direction (forward and rearward direction) in which the terminal sections80bare 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 sections80aor the terminal sections80bof the first bus bar module80are preferably aligned in the forward and rearward direction.

The upper portion of the first bus bar module80which is provided with the three terminal sections80aprotrudes upward from the battery case20, and the terminal sections80aare connected to the output terminal of the inverter47. The first bus bar module80runs through the space (cooling passage C1) formed between the battery40on a first row from a front and the battery40on a second row from the front, among the batteries40arranged in three rows in the forward and rearward direction. In other words, the first bus bar module80is placed in the front portion of the assembly of the batteries40. Since the first bus bar module80as the electric wire connecting the inverter47to the electric motor42runs through the interior (i.e., cooling passage C1) of the assembly of the batteries40, the first bus bar module80can be protected, as compared to a case where the first bus bar module80is placed between the battery case20and the batteries40. In the present embodiment, the first bus bar module80runs through the space formed between the batteries40aligned 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 batteries40in the rightward and leftward direction. Therefore, the first bus bar module80can be protected suitably.

Since the battery case20is provided with the terminal accommodating section23b(terminal box) for electrically connecting the first bus bar module80to the electric cables27(seeFIG. 1), an assembling operation can be performed more easily, than in a case where the first bus bar module80is directly connected to the electric cables27. Specifically, the terminal accommodating section23baccommodates an electric conductor93including bus bar terminal sections93aconnected to the terminal sections80bof the first bus bar module80and cable terminal sections93bconnected to the electric cables27(seeFIG. 1). The bus bar terminal sections93alead inward of the battery case20, while the cable terminal sections93blead outward of the battery case20.

The terminal accommodating section23bis located inward relative to the front, rear, right, and left outer edges of the battery case20when viewed from above. In this structure, for example, when the vehicle body falls, a portion of the battery case20which is other than the terminal accommodating section23bcollides with an obstacle first, and as a result, the terminal accommodating section23bis protected. Also, the terminal accommodating section23bis located above the lowermost end of the group of the batteries40. Therefore, when the vehicle body falls, the lowermost end of the battery case20collides with an obstacle before the terminal accommodating section23bcollides with the obstacle, and as a result, the terminal accommodating section23bis protected.

FIG. 10is a perspective view of a second bus bar module98ofFIG. 8. As shown inFIGS. 8 and 10, the plurality of bus bars82,83connecting the batteries40accommodated in the lower case23to the batteries40accommodated in the middle case21(seeFIG. 3) are configured such that the surfaces of intermediate portions82a,83athereof are joined to each other via an insulating material, and thereby the second bus bar module98is integrated. In this structure, a virtual line connecting one end portion of the bus bar82to the other end portion of the bus bar82and a virtual line connecting one end portion of the bus bar83to the other end portion of the bus bar83do not cross each other. Therefore, the bus bars82,83are bent to allow the intermediate portions82a,83ato contact each other.

FIG. 11is a perspective view of a third bus bar module99ofFIG. 8. As shown inFIGS. 8 and 11, bus bars84to89for directly connecting the batteries40to each other are placed in a space formed between the group of the batteries40and the upper wall (upper wall of the upper case22) of the battery case20(seeFIG. 5). The plurality of bus bars84to89, 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 module99.

The batteries40accommodated in the battery case20are electrically interconnected in series, via the bus bars82to89of the second bus bar module98and the third bus bar module99. The positive terminal and negative terminal at the terminal ends of the group of the batteries40connected in series are connected to the bus bars81(seeFIG. 7) provided in the electric component space to be connected to the inverter47.

As described above, the first to third bus bar modules80,98,99are a plurality of sub-assemblies each of which includes a plurality of bus bars which are integrated. Therefore, the many bus bars82to89,94to96are mounted more efficiently.

The first bus bar module80and the second bus bar module98run through the cooling passages C1, C2(seeFIG. 5), in the battery space S2in the interior of the battery case20. In other words, the cooling passages C1, C2with a relatively large dimension to cool the batteries40are used as the accommodating space in which the bus bars82,83,94to96are accommodated. The air blown by the fan48is introduced into the battery case20through the air inlet22g, takes heat out of the batteries40and the bus bars82,83,94to96while flowing through the cooling passages C1, C2, and is thereafter discharged to outside of the battery case20through an air outlet (not shown) provided on the battery case20.

In accordance with the above-described configuration, since the electric wire (first bus bar module80) connecting the inverter47to the electric motor42runs through the interior space of the battery case20, 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 module80can be covered by the battery case20, the external appearance of the electric vehicle can be improved. Furthermore, since the battery case20is interposed between the electric motor42and the inverter47in the vertical direction, a distance from the batteries40to the inverter47and a distance from the batteries40to the electric motor42can be reduced, and the first bus bar module80which is the electric wire connecting the inverter47to the electric motor42is allowed to run through the interior of the battery case20, which can reduce the length of the first bus bar module80. Moreover, since the inverter47is adjacent to the battery case20, the electric wire extending to outside of the battery case20can be reduced.

The electric wire connecting the inverter47to the electric motor42includes the first bus bar module80, as the running portion vertically running through the internal space of the battery case20, and the three electric cables27for a three-phase AC current connecting the first bus bar module80to the electric motor42are provided between the lower portion of the battery case20and the casing44of the electric motor42to couple the battery case20and the electric motor42to each other. In this configuration, even when the inverter47and the electric motor42are placed to be vertically spaced apart from each other with the battery case20interposed between the inverter47and the electric motor42, the three high-voltage electric cables27which 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 inverter47to the electric motor42runs through a region outside of the case20.

Since the three bus bars94to96for a three-phase AC current constitute the first bus bar module80by joining together their surfaces via the insulating material, the three bus bars94to96for a three-phase AC current can be accommodated in a compact manner in the limited space S2in the interior of the battery case20, and can be handled more easily during assembly. In addition, since the three bus bars94to96for 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 bars94to96affects the remaining bus bars of the bus bars94to96.

The first bus bar module80includes a portion extending through the interior of the battery case20and through the opening22bon the upper surface of the battery case20, and protruding upward. This portion is connected to the inverter47placed on the upper portion of the battery case20. Therefore, the electric components such as the inverter47can be mounted later to the upper portion of the battery case20which is closed. The first to third bus bar modules80,98,99run through the cooling passages C1, C2in the battery space S2in the interior of the battery case20. In this configuration, the space reserved to cool the batteries40is used as the space reserved to allow the electric wires (bus bars) to run therethrough, and as a result, the size of the battery case20is not increased. The air flowing through the cooling passages C1, C2takes heat out of the first to third bus bar modules80,98,99, as well as the batteries40, and thereby an increase in the electric resistances in the first to third bus bar modules80,98,99can be suppressed.

The terminal block of the inverter47and the terminal block of the electric motor42are placed inward relative to the front, rear, right, and left edges of the assembly of the batteries40and of the battery case20. Therefore, the electric wires can be placed inward relative to the contour of the battery case20, when viewed from above, to electrically connect the inverter47to the electric motor42. Since the electric component group46is placed outside of the battery case20, maintenance for the electric component group46can be performed more easily without a need to open the battery case20.

Since the electric component group46including the inverter47is placed on the upper case22detachably mounted to the middle case21of the battery case20, assembly of the power unit19can be carried out more easily in a state in which the electric components are mounted to the upper case22as a sub-assembly. When the battery case20is detached from the vehicle body, the electric component group46can be detached from the vehicle body together with the batteries40. This allows an operator to easily check the operation of the batteries40in the state in which the batteries40are detached from the vehicle body before or after shipping.

Since the electric component group46is placed above the batteries40, assembly of the electric component group46can be carried out more easily than in a case where the electric components are placed below the batteries40. Since the electric component group46including the inverter47is placed on the upper case22detachably mounted to the middle case21of the battery case20, assembly can be carried out more easily in a state in which the electric component group46is mounted to the battery case20as a sub-assembly. When the battery case20is detached from the vehicle body, the electric component group46can be detached from the vehicle body together with the batteries40. This allows the operator to easily check the operation of the batteries40and the like, in the state in which the batteries40are detached from the vehicle body before or after shipping.

The electric cables27are placed on the same side (in the present example, left side) with respect to the vehicle body as the side where the side stand17is placed. Therefore, when the side stand17is placed in the use position and the vehicle body is made to independently stand in the inclined state, the electric cables27are not seen easily and thereby the external appearance of the electric vehicle can be improved. Since the middle case21is made of metal, the electric wires in the interior of the battery case20can be suitably protected, and leakage of electromagnetic noise radiated from the bus bar modules80,98,99to outside of the battery case20can be suppressed. Since the electric cables27which are a portion of the electric wire connecting the inverter47to the electric motor42are short in length, a cover for covering the electric cables27can be reduced in size.

Since the electric cables27are positioned apart from the seat30with the batteries40located between the electric cables27and the seat30, it becomes possible to prevent a situation in which the electric cables27are 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 case20is smaller in dimension in the rightward and leftward direction than the front portion of the battery case20is, and the electric wires (first bus bar module80and the electric cables27) connecting the inverter47to the electric motor42are placed in the front portion of the group of the batteries40. Therefore, the electric wires can be laid out more flexibly while allowing the driver to easily grip the battery case20with their knees.

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 case20, other electric wires (e.g., electric cables) may be used. Or, a part or the entirety of the electric component group46including the inverter47may be placed inside of the battery case20. Or, the cooling medium pipes64,65may run through a region outside of the battery case20, instead of the interior of the battery case20. 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

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