Battery unit connection structure of electric vehicle

A vehicle can have a battery unit which includes paired supporting shafts protruding in opposite directions. A battery side connector can be supported coaxially with the supporting shafts in a turnable manner. The direction in which the battery side connector is fitted and connected is the direction orthogonal to the supporting shafts. A battery holding block includes paired engaging recessed portions and a vehicle body side connector. The supporting shafts of the battery unit are inserted into the engaging recessed portions from a direction approximately orthogonal to the shaft. The battery side connector is fitted and connected to the vehicle body side connector. The battery unit is operated to turn around the supporting shaft to a position where the battery unit is fixed with the battery holding block.

BACKGROUND

The present invention relates to a battery unit connection structure of an electric vehicle equipped with a detachable/attachable battery unit as a power supply source.

2. Description of the Related Art

There is known an electric vehicle such as a two-wheeled electric vehicle, in which a battery unit is detachably attached to a battery holding portion of a vehicle body (see, for example, Japanese Patent Publication No. 2008-062814 (Patent Document 1)).

In a battery unit connection structure of an electric vehicle described in Patent Document 1, a battery holding portion is provided at a base portion of a seat post supporting a seat. A battery unit is assembled in an inclined posture to the battery holding portion, and then turned so that the battery unit is positioned along the seat post.

To be specific, in the battery unit connection structure of an electric vehicle, paired supporting shafts projecting toward opposite directions are provided to protrude from outer side surfaces of the battery unit at a lower end thereof, and engaging recessed portions for turnably receiving the paired supporting shafts of the battery unit are provided in the battery holding portion on the vehicle body side. In addition, a battery side connector is provided on a lower surface of the battery unit at a position away from the supporting shafts, and a vehicle body side connector to be fitted and connected with the battery side connector is provided in the battery holding portion at a position corresponding to the battery side connector.

To attach the battery unit to the vehicle body, the paired supporting shafts are first engaged with the corresponding engaging recessed portions with the battery unit set in an inclined posture. In this state, the battery unit is turned around the supporting shafts to fit and connect the battery side connector to the vehicle body side connector. The battery unit is then fixed to the vehicle body by a locking device.

However, in the above-mentioned conventional battery unit connection structure, the battery side connector is connected to the vehicle body side connector by turning the battery unit after engaging the supporting shafts of the battery unit with the corresponding engaging recessed portions on the vehicle body side. Accordingly, an operator connects the battery side connector and the vehicle body side connector without visually checking the connectors. This requires careful work because an attempt to turn the battery unit while the battery side connector and the vehicle body side connector are not properly fit causes a large load to act on a joint of the connectors.

SUMMARY

Embodiments of the present invention aim to provide a battery unit connection structure of an electric vehicle capable of improving workability in attaching a battery unit, by enabling easier and a more reliable connection of a battery side connector to a vehicle body side connector when attaching the battery unit.

A first embodiment of the invention is a battery unit connection structure of an electric vehicle in which a battery unit is detachably attached to a battery holding portion of a vehicle body. The battery holding portion comprises paired engaging recessed portions into which supporting shafts of the battery unit are inserted from a direction orthogonal to the shaft to turnably hold the supporting shafts. A vehicle body side connector is fixedly installed between the paired engaging recessed portions and fitted and connected with a battery side connector. The battery unit comprises paired supporting shafts protruding in opposite directions from outer side surfaces, and the battery side connector supported coaxially with the paired supporting shafts in a turnable manner, and fitted and connected in a direction orthogonal to the supporting shafts. The paired supporting shafts of the battery unit are inserted into the corresponding engaging recessed portions of the battery holding portion from the direction orthogonal to the shaft, while the battery side connector is fitted and connected to the vehicle body side connector, and the battery unit is operated to turn around the supporting shafts to a position where the battery unit is fixed with the battery holding portion while causing the battery side connector to turn relative to the battery unit. Thus, the battery unit is connected and fixed with the battery holding portion.

A second embodiment of the invention is such that the engaging recessed portions of the battery holding portion open toward a direction in which the battery side connector is fitted and connected to the vehicle body side connector when the battery unit is in an initial attachment posture.

In a third embodiment of the invention, the battery unit further comprises a locking claw for locking the turning of the battery side connector, and a biasing spring for biasing the locking claw in a locking direction. The battery holding portion further comprises a release protrusion for displacing the locking claw against a force of the biasing spring to a lock release position, when the battery unit is pushed into a position where the battery side connector and the vehicle body side connector are fitted and connected.

In a fourth embodiment of the invention, the release protrusion is provided in the battery holding portion so that the release protrusion can be operated to protrude from the battery holding portion. The locking claw includes a lock hole into which the release protrusion operated to protrude is fitted to lock turning of the battery unit, when the locking claw is displaced to the lock release position and the battery unit is operated to turn around the supporting shafts to a predetermined turning position.

In a fifth embodiment, the battery holding portion further comprises a key cylinder for operating the release protrusion to protrude by use of an operation key.

In a sixth embodiment, a supporting protrusion is provided on an inner wall of each of the engaging recessed portions, the inner wall being approximately orthogonal to an insertion direction of the supporting shafts. A notch reaching a region including a rotational center is provided in an outer surface of each of the supporting shafts. The notch is formed to allow insertion of a tip end portion of the supporting protrusion to the region including the rotational center, when the supporting shafts are inserted into the corresponding engaging recessed portions from the direction orthogonal to the shaft, as well as to allow each of the supporting shafts to turn by a predetermined angle around the tip end portion of the supporting protrusion as the center. When the battery unit turns to the position where the battery unit is fixed with the battery holding portion, an edge of each of the supporting shafts facing the notch turns and comes to a back portion of the supporting protrusion so that the supporting shafts are prevented from coming off from the engaging recessed portions.

According to the first embodiment of the invention, the paired supporting shafts of the battery unit are inserted into the corresponding engaging recessed portions of the battery holding portion from the direction approximately orthogonal to the shaft, and the battery side connector is fitted and connected to the vehicle body side connector. In this state, while the battery side connector is turned relative to the battery unit, the battery unit can be turned by the predetermined angle around the supporting shaft to be fixed to the battery holding portion. Accordingly, when attaching the battery unit, the battery side connector can accurately and easily be connected to the vehicle body side connector in coaxial alignment with the supporting shaft. Hence, the present invention can improve workability in attaching the battery unit.

According to the second embodiment of the invention, the engaging recessed portions of the battery holding portion open in the same direction as the direction in which the battery side connector and the vehicle body side connector are fitted and connected. For this reason, it is possible to also connect the battery side connector to the vehicle body side connector, only by pushing in the battery unit so that the supporting shafts are inserted into the corresponding engaging recessed portions from the direction approximately orthogonal to the shaft. In other words, the terminal connection position is the position where the battery unit is caused to swing. Thus, it is possible to further improve workability in attaching the battery unit.

According to the third embodiment of the invention, in the stage before attaching the battery unit to the battery holding portion, the locking claw locks the turning of the battery side connector by the force of the biasing spring. Hence, when the battery unit is pushed in so that the supporting shafts are inserted into the corresponding engaging recessed portions from the direction approximately orthogonal to the shaft, the battery side connector is reliably fitted and connected to the vehicle body side connector. Moreover, after the battery side connector is fitted and connected to the vehicle body side connector, the release protrusion on the battery holding portion side displaces the locking claw to the lock release position to release the locking of the turning of the battery side connector. Accordingly, the following operation of turning the battery unit can be performed smoothly.

According to the fourth embodiment of the invention, when the locking claw is pushed by the release protrusion to release the locking of the turning, and the battery unit in this state is operated to turn and come to the predetermined turning position, the release protrusion is operated to protrude and fit in the lock hole to lock the turning of the battery unit. Thus, the turning of the battery unit can be locked easily by operating the release protrusion to protrude.

According to the fifth embodiment of the invention, the turning of the battery unit can be locked by operating the key cylinder by use of the operation key. Hence, it is possible to prevent the battery unit from being stolen by removing the operation key after locking.

According to the sixth embodiment of the invention, the supporting protrusion in the engaging recessed portion and the notch on the supporting shaft side allows not only a compact configuration, but also restriction of turning of the battery unit at the fixation position, and prevention of the battery unit from coming off the engaging recessed portions.

DETAILED DESCRIPTION

Hereinafter, a description is given of embodiments of the present invention with reference to the drawings. Note that front-rear, left-right and other directions in the following description are the same as the directions of a vehicle if not stated otherwise. In addition, in the drawings, an arrow FR indicates the front of the vehicle, an arrow LH indicates the left side of the vehicle, and an arrow UP indicates the upper part of the vehicle.

FIG. 1is a view showing a side of an electric motorcycle1which is one form of an electric vehicle.

The motorcycle1includes a main frame4joined to a head pipe3which turnably holds a handle post2. The main frame4extends obliquely downward toward the rear from the head pipe3, and a center frame5is joined integrally with a lower part of the rear end portion of the main frame4. A battery unit BU being a power supply source of the vehicle is detachably and attachably installed in front of the center frame5. In addition, the front end portion of a swing arm6supporting a rear wheel is pivotally supported in a swingable manner to the center frame5. Other than a rear wheel Wr, an electric motor (not shown) for driving the vehicle is attached to the swing arm6.

A bar handle7is attached to the handle post2. In addition, a front fork8supporting a front wheel Wf is connected to be integrally turnable with the handle post2.

Moreover, paired left and right rear frames9extend obliquely upward toward the rear from the rear end portion of the main frame4, and a seat10on which a driver sits is provided above base portions of the rear frames9. Additionally, the rear end portion of the swing arm6is connected to the rear frame9via a cushion unit11.

FIG. 2is a view obtained by enlarging an attachment portion of the battery unit BU.

As shown inFIG. 2, in this embodiment, an area between the main frame4and the center frame5is the area for placing the battery unit BU, and a battery holding block13(battery holding portion) is attached to the lower end of the center frame5via a bracket12protruding frontward. With the battery holding block13, the battery unit BU is assembled in a frontward-inclined state, turned by a predetermined angle to be brought to an upright posture after connectors are electrically connected, and then fixed within the aforementioned placement area.

FIG. 3is a perspective view showing a configuration of the inside of the battery holding block13and the battery unit BU.FIG. 4is a front view of the battery unit BU,FIG. 5is a sectional view of the battery holding block13and the battery unit BU, andFIGS. 6 and 7show steps for attaching the battery unit BU to the battery holding block13in the order of (A) to (D).

The battery unit BU is formed to have an almost rectangular horizontal cross section, and includes therein a battery module (not shown) and a battery side connector14for drawing power of the battery module to the outside. A stepped portion including a higher portion on the rear side of the vehicle body is provided on a bottom surface of the battery unit BU, and the battery side connector14is embedded near a corner of the stepped portion. The battery side connector14has four female terminal fittings14awhich are arranged linearly in a vehicle width direction.

Paired supporting shafts15projecting toward opposite directions are provided to protrude from side walls on both sides of the battery unit BU in the vehicle width direction. The supporting shafts15are provided in a protruding manner near the corner of the stepped portion. The supporting shaft15is formed in an almost cylindrical shape having a circular outer surface, with a later-described notch15aprovided in a part of an outer peripheral surface thereof. In addition, the battery side connector14embedded in the battery unit BU is turnably supported along the same shaft line as the supporting shafts15on both sides thereof. In other words, the battery side connector14is provided to be capable of turning relative to the battery unit BU, around a shaft line o1penetrating the center of the supporting shaft15.

Moreover, the battery side connector14is formed of an integral block having an almost L-shaped cross section, and the corner portion having an L-shaped cross section is the center of turning (o1). Additionally, a direction perpendicular to the shaft line o1being the rotational center of the battery side connector14is the direction in which the four terminal fittings14aare fitted and connected. Note that in the drawings, reference numeral16denotes distribution cables connecting the battery side connector14and the battery module provided in the battery unit BU.

As shown inFIG. 5, an opening17for exposing an end portion of the battery side connector14to the outside is formed near the corner portion of the bottom surface of the battery unit BU, the end portion being on the side where the terminal fittings14aare formed. The opening17is formed to extend toward the rear of the vehicle body, so as not to interfere with the battery side connector14when the battery side connector14turns relative to the battery unit BU. Additionally, in an initial posture of the battery side connector14, the terminal fittings14aface a direction approximately orthogonal to the bottom surface of the battery unit BU. The initial posture is maintained by engaging a locking claw18provided inside the battery unit BU with the battery side connector14.

The locking claw18is slidably held in a holder19fixedly installed in the battery unit BU. Holding walls19aof the holder19are set to be in parallel with openings of the terminal fittings14aof the battery side connector14in its initial posture. Moreover, a biasing spring20is interposed between the bottom of the holder19and the locking claw18, and the locking claw18is continuously biased toward its protruding direction by the biasing spring20. In a tip-end-side area of the locking claw18protruding from the holder19, an apex portion18ais provided on the front side of the vehicle body, and a flat tapered surface18bis provided closer to the rear of the vehicle body to be continuous with the apex portion18a. The apex portion18ais formed to have an arc-shaped cross section. Additionally, a later-mentioned lock hole21is formed in the tapered surface18b.

Provided in the approximate center of the battery side connector14in the vehicle width direction are a fitting slot22in which a tip end portion of the locking claw18is fitted, and a through hole23connecting an end surface of the battery side connector14and the bottom of the fitting slot22. The end surface is on the side on which the terminal fittings14aof the battery side connector14open.

The turning of the battery side connector14relative to the battery unit BU is locked by fitting the tip end portion of the locking claw18in the fitting slot22. In addition, the battery side connector14is configured such that when the tip end portion of the locking claw18receives an external force to be pushed back against the force of the biasing spring20for a predetermined amount or more, the tip end portion of the locking claw18comes out of the fitting slot22, and the locking of the turning of the battery unit BU is released. The through hole23is provided to be in parallel with the direction in which the terminal fittings14aof the battery side connector14open.

The battery holding block13includes paired holding brackets24provided to protrude from both end portions of the battery holding block13in the vehicle width direction to turnably hold the paired supporting shafts15of the battery unit BU. A vehicle body side connector25is arranged between the paired holding brackets24to be fitted and connected with the corresponding battery side connector14of the battery unit BU. A release pin26(release protrusion) protruding upward from the center of the vehicle body side connector25in the vehicle width direction. In the vehicle body side connector25, four terminal pins25aare provided in a protruding manner, and the four terminal pins25aare to be fitted and connected with corresponding terminal fittings14aof the battery side connector14. Moreover, two each of the terminal pins25aare arranged on both sides of the release pin26, and are arranged linearly together with the release pin26between the paired holding brackets. The release pin26is inserted in the through hole23of the battery side connector14. When the battery unit BU is pushed toward the battery holding block13in this state, the tip end portion of the release pin26comes into contact with the apex portion18aof the locking claw18to push the locking claw18until it reaches the lock release position.

As shown inFIGS. 3 and 7, an engaging recessed portion27is formed on each of the holding brackets24. The corresponding supporting shaft15on the battery unit BU side is inserted into the engaging recessed portion27from a direction orthogonal to the shaft. An opening of the engaging recessed portion27opens in the same direction (the direction in which the battery side connector14is fitted and connected) as the direction in which the terminal pins25aof the vehicle body side connector25protrude.

In addition, a supporting protrusion28is provided on an inner wall of the engaging recessed portion27, the inner wall being approximately orthogonal to the direction in which the supporting shaft15is inserted. The supporting protrusion28has an almost triangular shape with an apex whose angle is approximately 45°, and protrudes toward a center o2of an arc on the bottom side of the engaging recessed portion27. The tip end portion of the supporting protrusion28is in an arc shape having a predetermined radius and whose center coincides with the center o2of the arc of the engaging recessed portion27. Note that in this embodiment, the center o2of the arc on the bottom side of the engaging recessed portion27coincides with the center of turning (shaft line o1) of the supporting shaft15, when the supporting shaft15is inserted in the bottom portion of the engaging recessed portion27.

Meanwhile, the notch15aformed in the outer peripheral surface of each supporting shaft15reaches a region including the rotational center of the supporting shaft15, and has an almost fan shape with an apex whose angle is approximately 90°. A region at the center of the fan shape of the notch15ais formed in an arc shape whose center coincides with the rotational center of the supporting shaft15. The notch15aof each supporting shaft15is formed such that when the supporting shaft15is inserted in the corresponding engaging recessed portion from the direction approximately orthogonal to the shaft, the notch15aallows the tip end portion of the supporting protrusion28to be inserted in the region including the rotational center of the supporting shaft15, and also allows the supporting shaft15to turn by a predetermined angle around the tip end portion of the supporting protrusion28as the center.

After being inserted into the corresponding engaging recessed portion27from the direction approximately orthogonal to the shaft, the supporting shaft is operated to turn with the battery unit BU by approximately 45° toward a fixation position. Both of the notches15aare formed to allow this turning of the supporting shaft15. In addition, when the supporting shaft15is thus turned by approximately 45°, an edge of the supporting shaft15facing the notch15aturns and comes to a back portion side (the bottom side of the engaging recessed portion27) of the supporting protrusion28, whereby the supporting shaft15is prevented from coming off from the engaging recessed portion27.

A key cylinder29can be further provided in the battery holding block13.

FIG. 8is a view showing actions of the key cylinder29.

The key cylinder29is integrally attached to a back portion side (a lower side) of the vehicle body side connector25. The key cylinder29is turnably operated by inserting an operation key30in a key groove29a(seeFIG. 3), whereby an operation pin31is moved frontward and backward in the direction of the vehicle body side connector25.

The release pin26protruding upward from the center of the vehicle body side connector25is not fixed to the vehicle body side connector25, but is held to be capable of moving frontward and backward (in and out) in a base block of the vehicle body side connector25. A lower end of the release pin26protruding into the base block is in contact with the operation pin31of the key cylinder29. Hence, the position of the release pin26is changed by operating the key cylinder29with the operation key30. Note that in the drawings, reference numeral32denotes a return spring continuously biasing the release pin26in the backward direction.

FIGS. 9 and 10are views showing a state in which the release pin26and the locking claw18are engaged when the release pin26is operated in the protruding direction by the key cylinder29.

As can be seen in the drawings, when the battery unit BU is turned upward by a predetermined angle with the locking claw18, the tip end portion of the release pin26faces the lock hole21provided in the tapered surface18bof the locking claw18. When the release pin26is operated in the protruding direction by the key cylinder29in this state, the tip end portion thereof fits in the lock hole21. Thus, positions of the locking claw18and the holder19are fixed by the release pin26, whereby turning of the battery unit BU around the supporting shaft15is locked.

Hereinafter, attachment and detachment of the battery unit BU of the motorcycle1will be described.

When attaching the battery unit BU to the battery holding block13of the vehicle body, the operation pin31of the key cylinder29is retracted in advance, so that the release pin26is in its initial protrusion state (retracted state).

In addition, the locking claw18in the battery unit BU is fitted in the fitting slot22of the battery side connector14by the force of the biasing spring20. Accordingly, turning of the battery side connector14relative to the battery unit BU is locked, and the battery side connector14maintains its initial posture.

In this state, an operator holds the battery unit BU in its initial posture where it is inclined by a set angle, and then while maintaining this posture, inserts the supporting shafts15at both sides of the battery unit BU into the corresponding engaging recessed portions27of the battery holding block13from the direction approximately orthogonal to the shaft, as shown in parts (A) and (B) ofFIG. 7. At this time, the supporting protrusion28in each engaging recessed portion27is placed in the notch15aof the supporting shaft15, and the tip end portion of the supporting protrusion28comes into contact with the bottom portion of the arc shape of the notch15a.

Concurrently, the release pin26on the battery holding block13side is inserted in the through hole23of the battery side connector14as shown in parts (A) and (B) ofFIG. 6, and the terminal pins25aof the vehicle body side connector25are fitted and connected to corresponding terminal fittings14aof the battery side connector14. Then, the tip end portion of the release pin26inserted in the through hole23of the battery side connector14comes into contact with the apex portion18aof the locking claw18to push the locking claw18out of the fitting slot22. As a result, the battery side connector14is allowed to turn relative to the battery unit BU.

Moreover, this operation causes the center of the supporting shaft15and the shaft line o1penetrating the center of turning of the battery side connector14, to coincide with the center o2of the arc of the engaging recessed portion27on the battery holding block13side.

Next, the operator turns the battery unit BU by a predetermined angle around the supporting shaft15to bring the whole battery unit BU almost upstraight.

At this time, as shown in parts (C) and (D) ofFIG. 6, the locking claw18changes the direction of its surface in contact with the release pin26while being in sliding contact with the tip end portion of the release pin26. In the end, the tip end portion of the release pin26faces the lock hole21in the tapered surface18bof the locking claw18.

At this time, as shown in parts (C) and (D) ofFIG. 7, the supporting shafts15of the battery unit BU turn by a predetermined angle around the tip end portion of the supporting protrusion28in the engaging recessed portion27as the center, and finally the edge of the supporting shaft15facing the notch15aturns and comes to the back portion side of the supporting protrusion28. Hence, in this state, displacement of the supporting shaft (battery unit BU) toward the opening side of the engaging recessed portion27is restricted by the supporting protrusion28.

Thereafter as shown in parts (A) and (B) ofFIG. 8, the operator inserts the operation key30into the key cylinder29, and turns the operation key30to a predetermined position to make the operation pin31of the key cylinder29protrude therefrom. With this, the tip end portion of the release pin26is fitted in the lock hole21of the locking claw18, so that turning of the battery unit BU is locked while the battery unit BU is in the upstraight posture as shown inFIGS. 9 and 10. In this state, the operation key30is pulled out of the key cylinder29.

On the other hand, when detaching the battery unit BU attached to the vehicle body, the operation key30is inserted into the key cylinder29and turned in a direction opposite to that at the time of attachment to retract the release pin26. Since this operation releases the locking of the turning of the battery unit BU, the battery unit BU is turned around the supporting shaft15from this state to the initial attachment posture. Thereafter, pulling the battery unit BU in the initial attachment posture causes the supporting shafts15to come off from the corresponding engaging recessed portions27, and also disconnects the fitted and connected vehicle body side connector25and battery side connector14.

As has been described, the motorcycle1is configured such that the paired supporting shafts15of the battery unit BU are inserted into the corresponding engaging recessed portions on the vehicle body side from the direction approximately orthogonal to the shaft, and the battery side connector14is fitted and connected to the vehicle body side connector25. In this state, the whole battery unit BU can be turned to a fixation position, relative to the battery side connector14connected to the vehicle body side connector25. Accordingly, when attaching the battery unit BU, the battery side connector14can be accurately and easily connected to the vehicle body side connector25in coaxial alignment with the supporting shaft15.

Particularly in this embodiment, the engaging recessed portions27on the vehicle body side open in the same direction as the direction in which the battery side connector14and the vehicle body side connector25are fitted and connected. For this reason, it is possible to also fit and connect the battery side connector14and the vehicle body side connector25, only by pushing in the battery unit BU so that the supporting shafts15are inserted into the corresponding engaging recessed portions from the direction approximately orthogonal to the shaft.

Thus, it is extremely easy to assemble the battery unit BU in the motorcycle1.

Additionally, in the motorcycle1, the locking claw18for locking the turning of the battery side connector14and the biasing spring20for biasing the locking claw18in the locking direction are provided in the battery unit BU. Hence, when assembling the battery unit BU in the initial attachment posture, the turning of the battery side connector14can be restricted to easily and reliably fit and connect the battery side connector14and the vehicle body side connector25.

In the motorcycle, the release pin26for releasing the lock of the locking claw18when the battery side connector14and the vehicle body side connector25are fitted and connected is provided on the battery holding block13side. Hence, when the fitting and connecting of the battery side connector14and the vehicle body side connector25are completed, it is possible to smoothly transit to the following turning operation of the battery unit BU.

Furthermore, in the motorcycle1, the release pin26is capable of performing a protruding action, and the lock hole21in which the tip end portion of the release pin26is fitted is provided in the tapered surface18bof the locking claw18. Hence, after fitting and connecting the battery side connector14with the vehicle body side connector25and turning the battery unit BU to the predetermined position, it is possible to lock the turning of the battery unit BU relative to the battery holding block13by making the release pin26protrude so that the tip end portion thereof is fitted in the lock hole21. Accordingly, the battery unit BU can be fixed to the vehicle body with a compact configuration.

Particularly in this embodiment, a configuration is employed in which the release pin26is operated to protrude by operating the key cylinder29with the operation key30. For this reason, it is possible to prevent the battery unit BU from being stolen by removing the operation key30after locking.

Moreover, in the motorcycle1, a configuration is employed in which when the supporting shafts15of the battery unit BU are inserted into the corresponding engaging recessed portions27from the direction approximately orthogonal to the shaft, the supporting protrusion28in the engaging recessed portion27is inserted in the notch15aof the supporting shaft15. Thereafter, when the battery unit BU is turnably operated, the supporting shaft15rotates with the supporting protrusion28as the rotational center, and at the point when the battery unit BU turns to the fixation position, the edge of the supporting shaft15facing the notch15aturns and comes to the back portion of the supporting protrusion28. Hence, even though the configuration is compact, it is possible to restrict turning of the battery unit BU at the fixation position, and to prevent the battery unit BU from coming off the engaging recessed portions27.

Note that the present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, although the battery unit BU is attached such that it is inclined toward the front of the center frame5in the above embodiment, the battery unit BU may be attached such that it is inclined in the lateral direction of the vehicle body as in the modified examples shown inFIGS. 11 to 14. Configurations similar to those described above can be employed for the battery unit BU and the battery holding portion in these cases.

In the modified examples shown inFIGS. 11 to 14, a sub-frame50having an almost L-shape is joined to the lower end of a center frame5and the lower end of a front end portion of a main frame4. A battery unit BU is placed in a space having an almost trapezoidal shape surrounded by the center frame5, the main frame4, and the sub-frame50. In the modified example ofFIG. 11, the battery unit BU is turnably attached to the back of a front wall50aof the sub-frame50, and in the modified example ofFIG. 12, the battery unit BU is turnably attached below the main frame4. Meanwhile, in the modified example ofFIG. 13, the battery unit BU is turnably attached above a lower wall50bof the sub-frame50, and in the modified example ofFIG. 14, the battery unit BU is turnably attached to the front of the center frame5.

Moreover, although the electric motorcycle is described as an example of an electric vehicle in the above embodiment, the electric vehicle may be a three-wheeled vehicle or a four-wheeled vehicle.

EXPLANATION OF THE REFERENCE NUMERALS