Ground leakage detector, and method of detecting ground leakage in electric vehicle

A ground leakage detector for detecting a ground leakage in an electric vehicle including a battery, and a charging connector which is electrically connectable to a terminal member formed at one end of an outside electric wire through which electric power is supplied from outside to the battery, includes a connector connection section electrically connectable to the charging connector; a contactor configured to contact a vehicle body ground location in the electric vehicle; and a detecting circuit for detecting whether or not there is a ground leakage from the battery to the vehicle body ground location, based on a current flowing between the connector connection section and the contactor.

TECHNICAL FIELD

The present invention relates to a ground leakage detector, and a method of detecting a ground leakage in an electric vehicle.

BACKGROUND ART

A vehicle (hereinafter will be referred to as electric vehicle) which uses electric energy as a driving power source incorporates electric components such as a battery storing DC power, an inverter which converts the DC power stored in the battery into AC power, and an electric motor activated by the AC power output from the inverter. These electric components are accommodated in a case having an insulativity to be isolated (floating) from a vehicle body ground location maintained at a ground potential. For example, Patent Literature 1 discloses that a ground leakage is detected and a ground leakage location is estimated even in a state in which the battery is isolated from the vehicle body ground location.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

The ground leakage detector disclosed in Patent Literature 1 detects a ground leakage after systems (e.g., power supply system, measuring system, and control system) in the electric vehicle are activated. That is, the ground leakage detector disclosed in Patent Literature 1 is unable to detect a ground leakage before the systems in the electric vehicle are activated.

The present invention has been developed to solve the above described problem, and an object of the present invention is to provide a device and method which can easily detect a ground leakage regardless of whether or not a system in an electric vehicle is activated.

Solution to Problem

To solve the above described problem, according to an aspect of the present invention, there is provided a ground leakage detector for detecting a ground leakage in an electric vehicle including a battery, and a charging connector which is electrically connectable to a terminal member formed at one end of an outside electric wire through which electric power is supplied from outside to the battery, the ground leakage detector comprising: a connector connection section electrically connectable to the charging connector; a contactor configured to contact a vehicle body ground location in the electric vehicle; and a detecting circuit for detecting whether or not there is a ground leakage from the battery to the vehicle body ground location, based on a current flowing between the connector connection section and the contactor.

In accordance with this configuration, since the connector connection section of the ground leakage detector is electrically connected to the charging connector of the electric vehicle, the connector connection section can be placed at the electric potential corresponding to the terminal voltage of the battery of the electric vehicle. In other words, there is no need for the operation for sensing the terminal voltage of the battery in a state in which a dedicated connection terminal (e.g., alligator clip) is connected to both ends of the battery, to detect a ground leakage. In this state, by bringing the contactor into contact with the vehicle body ground location, it can be detected whether or not there is a ground leakage from the battery unit to the vehicle body ground location based on the current flowing between the connector connection section and the contactor. In brief, the ground leakage detector which is provided outside the electric vehicle and electrically connected to the charging connector detects a ground leakage. The ground leakage detector can detect whether or not there is a ground leakage, irrespective of whether or not the system in the electric vehicle is activated. Through the above described procedure, even before the system in the electric vehicle is activated, it can be detected whether or not there is a ground leakage in the battery, outside the electric vehicle.

In the above ground leakage detector, the connector connection section may be electrically connectable to a positive side and a negative side of the battery via the charging connector.

In accordance with this configuration, since the connector connection section is electrically connected to the charging connector, a ground leakage in both of the positive side and the negative side of the battery can be detected by switching a circuit.

In the above ground leakage detector, the detecting circuit may include: a switch for performing switching between a state in which one of electrodes of the battery and the vehicle body ground location are shorted via the contactor and a state in which one of electrodes of the battery and the vehicle body ground location are not shorted via the contactor; and an operation determiner section for determining whether or not the detecting circuit is operating correctly when one of electrodes of the battery and the vehicle body ground location are shorted by the switch.

In accordance with this configuration, the normal ground leakage detecting operation or the operation for determining whether or not the detecting circuit is operating correctly, i.e., the self-diagnostic operation, can be selected by using the switch as desired. This makes it possible to carry out the normal ground leakage detecting operation once it is determined that the detecting circuit is operating correctly.

In the above ground leakage detector, the electric vehicle may include: a first in-vehicle relay which is placed between the charging connector and the battery and connects the charging connector and the battery to each other or disconnects the charging connector and the battery from each other; and a vehicle body control unit for activating the first in-vehicle relay; and the charging connector and the connector connection section may be configured such that the ground leakage detector and the vehicle body control unit are mutually communicable; and the ground leakage detector may be configured to output to the vehicle body control unit a command for activating the first in-vehicle relay to connect the charging connector and the battery to each other, via the connector connection section and the charging connector, when the detecting circuit is activated.

In accordance with this configuration, the ground leakage detecting operation is not performed as soon as the connector connection section is electrically connected to the charging connector, but the first in-vehicle relay is activated to connect the charging connector and the battery to each other only when the ground leakage detecting operation is performed. Therefore, it becomes possible to perform the ground leakage detecting operation using the electric power stored in the battery.

In the ground leakage detector, the electric vehicle may include: a second in-vehicle relay which is electrically connected to a system operation power supply and closes a contact of the second in-vehicle relay before a system is activated; the ground leakage detector may be configured to output to the vehicle body control unit a command for activating the second in-vehicle relay to close the contact of the second in-vehicle relay, via the connector connection section and the charging connector, when the detecting circuit is activated.

In accordance with this configuration, after connection of the connector is established, the commands for closing the contacts of the first and second in-vehicle relays can be provided, and a circuit for detecting a ground leakage can be configured even before the system is activated. Thus, the ground leakage detecting operation can be performed even before the system is activated.

In the ground leakage detector, the detecting circuit may be configured to output to the vehicle body control unit a command for activating the first in-vehicle relay to disconnect the charging connector and the battery from each other, via the connector connection section and the charging connector, when a predetermined termination condition is satisfied.

In accordance with this configuration, when the predetermined termination condition, for example, a time that passes from the ground leakage detecting operation is initiated reaches a predetermined threshold time, the first in-vehicle relay is activated to disconnect the charging connector and the battery from each other. Therefore, it becomes possible to prevent a ground leakage detection state from continuing undesirably, and lessen consumption of the electric power stored in the battery. The predetermined termination condition may be such that the time that passes from when the ground leakage detecting operation is initiated reaches the predetermined threshold time or another condition. For example, the predetermined termination condition may be such that the ground leakage detecting operation for the positive side and the negative side is terminated or a ground leakage at the positive side or the negative side is detected.

In the ground leakage detector, the detecting circuit may further include: a voltage source which is connected to the connector connection section in parallel with the battery and has a voltage lower than a terminal voltage of the battery; and wherein when the operation determiner section may determine whether or not the detecting circuit is operating correctly, the detecting circuit may be electrically disconnected from the battery via the charging connector and the connector connection section and cause one of electrodes of the voltage source and the vehicle body ground location to be shorted via the contactor.

In accordance with this configuration, in the self-diagnostic process, by utilizing the voltage of the voltage source (voltage derived by AC/DC converting a voltage of built-in battery or power supply utility, etc.) of the ground leakage detector which is lower than the terminal voltage of the battery of the electric vehicle, rather than the terminal voltage of the battery, consumption of the electric power stored in the battery can be lessened. Since the voltage of the voltage source of the ground leakage detector is lower than the terminal voltage of the battery of the electric vehicle, it becomes possible to lessen a current flowing when one of the electrodes of the voltage source and the vehicle body ground location are shorted via the contactor in the self-diagnostic process. Thus, safety of the ground leakage detector can be improved. Furthermore, a ground leakage can be detected even though the SOC of the battery is less.

The ground leakage detector may be mounted in an outside charger electrically connectable to the charging connector.

In accordance with this configuration, the connector of the outside charger which is electrically connectable to the charging connector can be efficiently utilized. Therefore, it is not necessary to provide another connector intended for the ground leakage detector mounted in the outside charger.

The ground leakage detector may automatically detect whether or not there is a ground leakage when charging is initiated or terminated.

In accordance with this configuration, it becomes possible to automatically confirm whether or not the charging will be or has been performed correctly, when the outside charger initiates or terminates the charging of the battery.

The ground leakage detector may regularly detect whether or not there is a ground leakage in a state in which the outside charger is electrically connected to the charging connector for a long period of time.

In accordance with this configuration, it becomes possible to detect whether or not there is a ground leakage by efficiently utilizing the long period of time for which the electric vehicle electrically connected to the charging connector is in storage.

To solve the above described problem, according to another aspect of the present invention, there is provided a method of detecting a ground leakage in an electric vehicle including a battery, and a charging connector which is electrically connectable to a terminal member formed at one end of an outside electric wire through which electric power is supplied from outside to the battery, by using a ground leakage detector including a connector connection section electrically connectable to the charging connector and a contactor configured to contact a vehicle body ground location in the electric vehicle, the method comprising: electrically connecting the connector connection section to the charging connector; bringing the contactor into contact with the vehicle body ground location; and detecting whether or not there is a ground leakage from the battery to the vehicle body ground location, based on a current flowing between the connector connection section and the contactor.

In accordance with this method, detection of a ground leakage in the battery can be easily performed outside the electric vehicle, even before the system in the electric vehicle is activated.

To solve the above described problem, according to another aspect of the present invention, there is provided a method of detecting a ground leakage in an electric vehicle including a battery, an in-vehicle ground leakage detector for detecting a ground leakage from the battery to a vehicle body ground location maintained at a ground potential, and a charging connector which is electrically connectable to a terminal member formed at one end of an outside electric wire through which electric power is supplied from outside to the battery and communicable with the in-vehicle ground leakage detector, by using a control device including a connector connection section which is electrically connectable to the charging connector and communicable with the in-vehicle ground leakage detector, the method comprising: electrically connecting the connector connection section to the charging connector; transmitting an activation command from the control device to the in-vehicle ground leakage detector via the connector connection section and the charging connector; receiving by the in-vehicle ground leakage detector the activation command from the control device and detecting by the in-vehicle ground leakage detector whether or not there is a ground leakage from the battery to the vehicle body ground location; transmitting information indicative of a result of detection as to whether or not there is a ground leakage from the in-vehicle ground leakage detector to the control device via the charging connector and the connector connection section; and receiving by the control device the information indicative of the result of detection as to whether or not there is a ground leakage from the in-vehicle ground leakage detector via the charging connector and the connector connection section.

In accordance with this method, detection of a ground leakage in the battery can be easily performed outside the electric vehicle, even before the system in the electric vehicle is activated.

The above and further objects, features and advantages of the invention will more fully be apparent from the following detailed description of a preferred embodiment with reference to the accompanying drawings.

Advantageous Effects of Invention

In accordance with the present invention, it is possible to provide a device and method which can easily detect a ground leakage irrespective of whether or not a system in an electric vehicle is activated.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, throughout the drawings, the same or corresponding components are designated by the same reference numerals, and will not be described repeatedly, unless otherwise noted.

Exemplary Configuration of Overall System

In Embodiment 1 of the present invention, a charging connector used for charging a battery, which is equipped in an electric vehicle, is utilized as a connector for electrically and communicatively connecting a ground leakage detector outside the electric vehicle and the electric vehicle to each other, and a ground leakage in the electric vehicle can be detected even before a system in the electric vehicle is activated.

FIG. 1is a view showing an example of a left side view of an electric vehicle and an example of an outside connection of the electric vehicle, as an exemplary configuration of an overall system according to Embodiment 1 of the present invention. Although an electric motorcycle is exemplarily shown as the electric vehicle inFIG. 1, the electric vehicle is not limited to the electric motorcycle, but may be another straddle electric vehicle (electric three-wheeled vehicle or the like), an electric four-wheeled vehicle having a living space such as a multi-purpose vehicle, or an electric vehicle other than the vehicle, such as a small boat. Or, the electric vehicle may be a hybrid electric vehicle, incorporating an internal combustion engine in addition to an electric motor.

As shown inFIG. 1, the electric motorcycle1includes a front wheel2which is a driven wheel, a rear wheel3which is a drive wheel, a vehicle body frame4which is disposed between the front wheel2and the rear wheel3, and an electric motor5mounted to the vehicle body frame4. The electric motorcycle1is not equipped with an internal combustion engine and is configured to rotate the rear wheel3by driving power generated in the electric motor5.

The front wheel2is rotatably mounted to the lower portion of a front fork6extending substantially vertically such that it is inclined at a certain caster angle. A steering shaft7is coupled to the upper portion of the front fork6, and a bar-type handle8is attached to the upper portion of the steering shaft7. A right grip of the handle8is a throttle grip which is operated by the rider to adjust the driving power generated in the electric motor5.

The vehicle body frame4includes a head pipe11, a pair of right and left and a pair of upper and lower main frames12, a pair of right and left down frames13, a pair of right and left pivot frames14, a pair of right and left swing arms15, and a seat frame16. The head pipe11supports the steering shaft7such that the steering shaft7is rotatable.

The seat frame16supports a seat (not shown) on which the rider and a passenger are seated in a forward or rearward direction.

The electric motor5is placed in a region which is below the down frame13and in front of the pivot frame14. The driving power generated in the electric motor5is transmitted to the rear wheel3via a driving power transmission mechanism17. The electric motor5is accommodated in a motor case18having an insulativity. The motor case18accommodates a transmission (not shown) constituting the driving power transmission mechanism17together with the electric motor5, and is suspended from the down frame13and the pivot frame14. The transmission may be a multistage transmission or a gearless transmission. Also, the transmission may be a manual transmission or an automatic transmission.

The electric motorcycle1incorporates an inverter case19having an insulativity and a battery case80having an insulativity, in addition to the motor case18accommodating the electric motor5. The inverter case19accommodates electric components including an inverter20. The battery case80accommodates the electric components including the battery unit60. The inverter case19is placed in a space of a substantially-inverted triangular space when viewed from a side, which is surrounded by the main frame12, the pivot frame14and the seat frame16, and positioned just behind the lower rear end portion of the battery case80. The battery case80is placed between the pair of right and left main frames12, above the lower portions of the pair of right and left down frames13, and forward relative to the pivot frames14, and sandwiched between the front wheel2and the rear wheel3in the forward or rearward direction.

The battery case80is provided with a charging connector49used for charging a battery unit60from outside the electric motorcycle. For example, a fitting (mounting) section of the charging connector49may be exposed to the outer surface of the battery case80, or placed in an opening (charging port) of the battery case80and this opening may be covered with a specified cover.

The fitting section of the charging connector49includes a pin attached to the end portion of a charging wire491extended from the battery unit60and a pin attached to the end portion of a communication wire492extended from a vehicle body control unit59as will be described later. As shown inFIG. 1, the charging connector49is electrically connectable to a ground leakage detector100which is used when an operator carries out maintenance as well as an outside charger (not shown) for the battery unit60.

The ground leakage detector100detects a ground leakage from the battery unit60to a vehicle body ground location such as the vehicle body frame4which is maintained at a ground potential. The ground leakage detector100also has a function for intentionally shorting the battery unit60and the vehicle body ground location such as the vehicle body frame4without actually causing a ground leakage in the electric motorcycle1for a self-diagnostic process. The ground leakage detector100includes a connector101having a pin fitted to a pin of the charging connector49.FIG. 1shows a state in which the pin of the charging connector49and the pin of the connector101are fitted to each other and thereby the ground leakage detector100and the electric motorcycle1are electrically and communicatively connected to each other. The ground leakage detector100includes a contactor (probe)109for contacting the vehicle body ground location such as the vehicle body frame4which is maintained at a ground potential, in the electric motorcycle1. The contactor109is formed in the end portion of a cable150extended from the ground leakage detector100.

[Exemplary Configuration of Electric System]

FIG. 2is a block diagram mainly showing electric components and electric wires thereof, as an exemplary configuration of an electric system in the electric motorcycle1ofFIG. 1.

As shown inFIG. 2, the battery unit60includes a plurality of battery modules61and a battery frame64and is a unit which serves as a high-voltage and DC power single secondary battery. Each of the battery modules61includes a plurality of battery cells62and a module casing63in a rectangular parallelepiped shape, for storing the plurality of battery cells62. Each of the battery cells62is a secondary battery which is capable of storing DC power, and is, for example, a lithium ion battery or nickel metal hydride battery. The plurality of battery cells62are aligned and electrically connected to each other in the interior of the module casing63. The plurality of battery modules61are densely arranged in the interior of the battery case80and electrically connected in series, in a state in which they are connected to and fastened to the battery frame64.

As should be understood from the above, the battery unit60is configured such that many battery cells62are connected in series in an electrical sense, and as a result, serves as the secondary battery of high-voltage DC power (e.g., 200 to 300V). The battery unit60is electrically connected to the charging connector49via a charging wire491composed of a P-side (positive-side) charging wire491pand an N-side (negative-side) charging wire491nand electrically and mechanically connected to the inverter20via a high-voltage electric wire31composed of a P-side power supply wire31pand an N-side power supply wire31n. The inverter20converts the high-voltage DC power supplied from the battery unit60into three-phase AC power in accordance with a torque command or the like from the vehicle body control unit59, and supplies the three-phase AC power to the electric motor5via a three-phase AC wire32. The electric motor5is activated by the AC power supplied from the inverter20to generate driving power corresponding to electric characteristics such as a current.

A P-side inverter relay36is provided on the P-side power supply wire31pof the high-voltage electric wire31. A bypass wire33which branches from the P-side power supply wire31pis provided in parallel with the P-side inverter relay36. A current restricting resistor34and an anti-rush-current relay35are arranged in series on the bypass wire33. An N-side inverter relay37is provided on the N-side power supply wire31nof the high-voltage electric wire31.

An in-vehicle ground leakage detector300is electrically connected to a wire301which branches from the high-voltage electric wire31in a location between the battery unit60, and the P-side inverter relay36and the N-side inverter relay37. The in-vehicle ground leakage detector300detects a ground leakage from the battery unit60to the vehicle body ground location such as the vehicle body frame4which is maintained at a ground potential. For example, the in-vehicle ground leakage detector300is connected to the vehicle body frame4which is maintained at a ground potential via a ground wire302, in addition to a high-voltage wire301which branches from the high-voltage electric wire31at a location which is between the battery unit60and the inverter relays (36,37). The in-vehicle ground leakage detector300is configured such that, for example, two ground leakage detecting resistors are connected in series and the connection points of the ground leakage detecting resistors are connected to the ground potential. The in-vehicle ground leakage detector300is configured to detect whether or not a ground leakage path is formed from the battery unit60to the vehicle body frame4according to voltage drops generated in the ground leakage detecting resistors, respectively. The in-vehicle ground leakage detector300may be capable of directly activating the inverter relays (36,37) to disconnect the battery unit60and the inverter20from each other when it detects a ground leakage in the battery unit60, in addition to the detection of a ground leakage in the battery unit60. Or, the in-vehicle ground leakage detector300may transmit to the vehicle body control unit59a result of detection of a ground leakage, to cause the vehicle body control unit59to activate the inverter relays (36,37).

The inverter case19contains a smoothing capacitor38, the electrodes of which are connected to the P-side power supply wire31pand the N-side power supply wire31n. At the activation of the system in the electric motorcycle1, it becomes possible to prevent a rush current with an excessively great magnitude from flowing through the inverter20by suitably selecting OPEN/CLOSE of the relays (35to37), even under a state in which charges are not accumulated in the smoothing capacitor38. Current meter(s)53is/are attached onto the P-side power supply wire31p, the N-side power supply wire31n, and/or the bypass wire33. InFIG. 2, a case where the current meter53is attached only on the P-side power supply wire31pis exemplarily shown.

A service plug40is provided on a connection wire39connecting the battery modules61placed adjacently to each other. The service plug40includes a plug41for performing switching between continuity (conduction) and cut-off (disconnection) of the connection wire39and a fuse42for cutting-off (disconnecting) the connection wire39if a current with an excessively great magnitude flows therethrough. A maintenance operator operates the plug41manually to enable switching between a power supply state in which the connection wire39is placed in a conductive state and the electric power can be supplied from the battery unit60to the electric motor5and a cut-off (disconnection) state in which the connection wire39is placed in a cut-off state and the electric power supplied from the battery unit60to the electric motor5is cut off.

The electric motorcycle1includes a low-voltage battery43which is a secondary battery of low-voltage DC power (e.g., 12V), separately from the battery unit60which is an electric power supply for the electric motor5. The low-voltage battery43is connected to a power load other than the electric motor5, via a low-voltage electric wire44. The power load which uses the low-voltage battery43as the electric power supply includes, for example, a battery monitoring unit58for monitoring the SOC (state of charge) of the battery unit60, and a vehicle body control unit59for controlling the overall electric motorcycle1, including control for activating the electric motor5and the inverter20. Note that the battery monitoring unit58is able to activate the relays (35to37) so that the high-voltage electric wire31between the battery unit60and the inverter20is disconnected according to the SOC of the battery unit60. The vehicle body control unit59mutually communicates with the battery monitoring unit58and shares the information indicative of the SOC of the battery unit60with the battery monitoring unit58. The vehicle body control unit59activates the relays (35to37) based on the information indicative of the SOC of the battery unit60or outputs a desired torque command to the inverter20. In addition, the power load which uses the low-voltage battery43as the electric power supply includes a lighting device such as a head light, a tail lamp, and a direction indicator, instruments (gauges) such as a speed indicator, and a display unit.

The low-voltage battery43is connected to a DC/DC converter45via a low-voltage converter wire46composed of a P-side power supply wire46pa and an N-side power supply wire46n. The DC/DC converter45is connected to the P-side power supply wire31pand the N-side power supply wire31nof the high-voltage electric wire31via a high-voltage converter wire47composed of a P-side power supply wire4′7pand an N-side power supply wire47n. A DC/DC converter relay48is provided on a P-side power supply wire4′7pand an N-side power supply wire47nof the high-voltage converter wire47. InFIG. 2, a case where the DC/DC converter relay48is provided only on the high-voltage power supply wire4′7pis exemplarily shown.

The high-voltage electric wire31is connected to the charging connector49via the charging wire491composed of the P-side charging wire491pand the N-side charging wire491n. A P-side charging relay51is provided on the P-side charging wire491p, while an N-side charging relay52is provided on the N-side charging wire491n. As described above, the charging connector49includes pins formed at the end portion of the P-side charging wire491pand at the end portion of the N-side charging wire491n, and the pin formed at the end portion of the communication wire492for use in communication between the vehicle body control unit59and the ground leakage detector100. The charging connector49is a connector electrically connected to an outside charger for charging the battery unit60and electrically connected to the connector101of the ground leakage detector100. In brief, the charging connector49is used as the connector electrically connecting the ground leakage detector100to the electric motorcycle1.

In a state in which the outside charger is electrically connected to the charging connector49, the electric power is supplied from the outside charger to the battery unit60via the charging wire491and the high-voltage electric wire31and charged into the battery unit60. The electric power supplied from the outside charger can also be charged into the low-voltage battery43. Further, during deceleration of the electric motorcycle1, the electric motor5operates as an electric generator. In this case, the inverter20converts the AC power (regenerative electric power) generated by the electric motor5into DC power which can be charged into the battery unit60and the low-voltage battery43. Or, the DC/DC converter45converts the DC power stored in the battery unit60into DC power for the low-voltage battery43, and this DC power can be charged into the low-voltage battery43.

[Exemplary Configuration of Ground Leakage Detector]

FIGS. 3A and 3Bare views showing an exemplary circuit configuration of the ground leakage detector100ofFIG. 1.FIGS. 3A and 3Bshow a case where the connector101electrically connected to the charging connector49is integrated with the ground leakage detector100, for the sake of simplified illustration.

The ground leakage detector100is a portable (mobile) ground leakage detector which can be carried by a maintenance operator. The ground leakage detector100ofFIG. 3Aincludes a P-side connector terminal TP connected to the pin of the charging connector49which is the end portion of the P-side charging wire491pextended from the P-side of the battery unit60, an N-side connector terminal TN connected to the pin of the charging connector49which is the end portion of the N-side charging wire491nextended from the N-side of the battery unit60, a control terminal C connected to the pin of the charging connector49which is the end portion of the communication wire492extended from the vehicle body control unit59, and a contactor connection terminal TG connected to one end of the cable150extended from the contactor109. In brief, as the pins of the charging connector49, there are three pins corresponding to the terminals (TP, TN, C) other than the contactor connection terminal TG.

In contrast, the ground leakage detector100ofFIG. 3Bdoes not include the contactor109, unlike the ground leakage detector100ofFIG. 3A. This ground leakage detector100ofFIG. 3Bis electrically connectable to the vehicle body ground location such as the vehicle body frame4via the charging connector49. The ground leakage detector100ofFIG. 3Bis different from the ground leakage detector100ofFIG. 3Ain that a vehicle body ground terminal BG is provided instead of the contactor connection terminal TG. Therefore, the ground leakage detector100ofFIG. 3Bincludes four pins corresponding to the terminals (TP, TN, C) other than the contactor connection terminal TG and the vehicle body ground terminal BG respectively, as the pins of the charging connector49. The ground leakage detector100ofFIG. 3Aand the ground leakage detector100ofFIG. 3Bmay further include a ground terminal G which determines the ground potential inside the detector so that it is equal to the ground potential of the vehicle body. In this case, the ground leakage detector100ofFIG. 3Aincludes four pins (pins corresponding to terminals TP, TN, C, G) and the ground leakage detector100ofFIG. 3Bincludes five pins (pins corresponding to terminals TP, TN, C, G, BG), as the pins of the charging connector49.

The ground leakage detector100is configured such that ground leakage detecting resistors Rp, Rn are connected in series between the P-side connector terminal TP and the N-side connector terminal TN. An SPST (single pole, single throw) switch SW3A is provided on a wire between the P-side connector terminal TP and the ground leakage detecting resistor Rp, while an SPST switch SW3B is provided on a wire between the N-side connector terminal TN and the ground leakage detecting resistor Rn. The P-side connector terminal TP and N-side connector terminal TN, and the switch SW3A and the switch SW3B implement the connector connection section configured to be electrically connectable to the P-side and N-side of the battery unit60via the charging connector49. The connection point of the ground leakage detecting resistors Rp, Rn is connected to the contactor connection terminal TG. Therefore, when the contactor109contacts the vehicle body frame4maintained at the ground potential, the electric potential of the connection point of the ground leakage detecting resistors Rp, Rn becomes the ground potential of the vehicle body frame4.

The ground leakage detector100is configured such that a built-in battery107, an SPST switch MSW, an SPST switch SW1, and the coil of an auxiliary relay ASW are connected in series. One end of the resistor Rg is connected to one end of the contact (contact point) of the auxiliary relay ASW, while the other end of the contact (contact point) of the auxiliary relay ASW is connected to the contactor connection terminal TG. The other end of the resistor Rg is connected to a fixed contact (contact point) of an SPDT (single pole, double throw) switch SW2. One of movable contacts (contact points) of the switch SW2is connected to the P-side connector terminal TP, while the other of the movable contacts of the switch SW2is connected to the N-side connector terminal TN. A voltage detector108for detecting a terminal voltage of the battery unit60is connected in parallel with the movable contacts of the switch SW2.

The ground leakage detector100includes a control unit112and an alarm unit116which are activated by the built-in battery107. The control unit112includes a detecting section113for detecting whether or not there is a ground leakage from the battery unit60to the vehicle body ground location such as the vehicle body frame4, based on currents (specifically voltage drops ΔVp, ΔVn generated in the ground leakage detecting resistors Rp, Rn) flowing between the connector connection section (TP, TN, SW3A, SW3B) and the contactor109, an operation determiner section114for determining (self-diagnosing) whether or not a ground leakage is detected when the switch SW1is ON and thereby a short circuit is formed between one of the positive electrode and negative electrode of the battery unit60and the vehicle body ground location such as the vehicle body frame4, via the contactor109, and a counting section115for counting a time that passes from when detection of a ground leakage is initiated. Further, the control unit112includes a switch control section (not shown) for controlling the states of the switches (MSW, SW1, SW2, SW3A, SW3B), and a communication processing section (not shown) which performs communication (e.g., CAN [controller area network] communication) with the vehicle body control unit59in the electric motorcycle1via the control terminal C and the charging connector49. The control unit112is implemented by a CPU (central processing unit), a DSP (digital signal processor), a microcomputer, a logic circuit, etc. The control unit112may be configured as a plurality of control units which cooperate with each other to perform distributed control. The alarm unit116includes an LED (light-emitting diode)117and a speaker118. When the detecting section113of the control unit112detects a ground leakage, the LED117lights-up, and the speaker118outputs an alarm sound indicating that a ground leakage is detected.

[Exemplary Operation of Ground Leakage Detector]

The exemplary operation of the ground leakage detector100ofFIG. 3Awill be described with reference toFIGS. 4 and 5. The exemplary operation of the ground leakage detector100ofFIG. 3Bis different from the exemplary operation of the ground leakage detector100ofFIG. 3Aonly in that the contactor109does not contact the vehicle body ground location, and will not be described repeatedly.FIG. 4is a view for explaining the exemplary operation of the ground leakage detector100which is performed when a ground leakage occurs in the positive side (P-side) of the battery unit60according to Embodiment 1 of the present invention.FIG. 5is a view for explaining the exemplary operation of the ground leakage detector100which is performed when a ground leakage occurs in the negative side (N-side) of the battery unit60according to Embodiment 1 of the present invention. In the examples ofFIGS. 4 and 5, it is supposed that in the electric motorcycle1, the contact of the P-side charging relay51and the contact of the N-side charging relay52which are between the battery unit60and the charging connector49are closed, while in the ground leakage detector100, the connector101is electrically connected to the charging connector49of the electric motorcycle1.

It is supposed that both of the switch SW3A and the switch SW3B are closed, the ground leakage detector100is electrically connected to the P-side and N-side of the battery unit60, and there is no ground leakage in the battery unit60. In this case, the terminal voltage of the battery unit60is applied to the P-side connector terminal TP and the N-side connector terminal TN of the ground leakage detector100. Under this condition, when the contactor109is brought into contact with the vehicle body ground location such as the vehicle body frame4, the contactor connection terminal TG and the connection point of the ground leakage detecting resistors Rp, Rn in the ground leakage detector100are maintained at the ground potential. Thereby, in the ground leakage detector100, a voltage corresponding to an electric potential difference between the electric potential at the P-side of the battery unit60and the ground potential is applied to the ground leakage detecting resistor Rp, and a voltage corresponding to an electric potential difference between the electric potential at the N-side of the battery unit60and the ground potential is applied to the ground leakage detecting resistor Rn. Hereinafter, this state will be referred to as a “correct state.”

FIG. 4exemplarily shows a state in which a ground leakage (shorting) has actually occurred at the P-side of the battery unit60. Specifically, there is formed a current path (hereinafter will be referred to as ground leakage path, represented by a dashed line inFIG. 4) through which a ground-fault current flows from the ground-fault point P1at the P-side of the battery unit60toward the vehicle body frame4via an impedance to ground (not shown). When the switch SW3B is closed, the ground leakage detector100is electrically connected to only the N-side of the battery unit60via the charging connector49. The ground-fault current which has flowed from the ground-fault point P1toward the vehicle body frame4via the ground leakage path, is returned to the ground-fault point P1via a current path represented by a bold line inFIG. 4. The current path represented by the bold line inFIG. 4extends sequentially through the contactor109, the cable150, the contactor connection terminal TG, the ground leakage detecting resistor Rn, the switch SW3B, the N-side connector terminal TN, and the charging connector49. This causes a voltage drop ΔVn corresponding to the ground-fault current to be generated between both ends of the ground leakage detecting resistor Rn. The ground leakage detector100can detect whether or not there is a ground leakage at the P-side of the battery unit60, by detecting whether or not the voltage drop ΔVn is generated.

FIG. 5exemplarily shows a state in which a ground leakage (shorting) has actually occurred at the N-side of the battery unit60. Specifically, there is formed a ground leakage path (represented by a dashed line inFIG. 5) through which a ground-fault current flows is formed from the ground-fault point P2at the N-side of the battery unit60toward the vehicle body frame4via an impedance to ground (not shown). Since the switch SW3A is closed, the ground leakage detector100is electrically connected to only the P-side of the battery unit60via the charging connector49. The ground-fault current which has flowed from the ground-fault point P2toward the vehicle body frame4via the ground leakage path is returned to the ground-fault point P2via a current path represented by a bold line inFIG. 5. The current path represented by the bold line inFIG. 5extends sequentially through the contactor109, the cable150, the contactor connection terminal TG, the ground leakage detecting resistor Rp, the switch SW3A, the P-side connector terminal TP and the charging connector49. This causes a voltage drop ΔVp corresponding to the ground-fault current to be generated between both ends of the ground leakage detecting resistor Rp. The ground leakage detector100can detect whether or not there is a ground leakage at the N-side of the battery unit60, by detecting whether or not the voltage drop ΔVp is generated.

In accordance with the above described exemplary operation, by electrically connecting the connector connection section (TP, TN, switches SW3A, SW3B) to the charging connector49of the electric motorcycle1, the connector connection section of the ground leakage detector100can be placed at the electric potential corresponding to the terminal voltage of the battery unit60of the electric motorcycle1. In other words, there is no need for the operation for sensing the terminal voltage of the battery unit60in a state in which a dedicated connection terminal (e.g., alligator clip) is connected to both ends of the battery unit60to detect a ground leakage. In this state, by bringing the contactor109into contact with the vehicle body ground location such as the vehicle body frame4, it can be detected whether or not there is a ground leakage from the battery unit60to the vehicle body ground location based on the current flowing between the connector connection section and the contactor109. In brief, the ground leakage detector100which is provided outside the electric motorcycle1and electrically connected to the charging connector49detects a ground leakage. Therefore, it can be detected whether or not there is a ground leakage, irrespective of whether or not the system in the electric motorcycle1is activated. Through the above described procedure, even before the system in the electric motorcycle1is activated, it can be detected whether or not there is a ground leakage in the battery unit60, outside the electric motorcycle1.

In addition, in accordance with the above described exemplary operation, by electrically connecting the connector connection section to the charging connector49, the connector connection section can be placed at the electric potential at the P-side or the N-side of the battery unit60. This makes it possible to select detection of a ground leakage at the P-side of the battery unit60or the N-side of the battery unit60, as desired.

In accordance with the ground leakage detector100ofFIG. 3A, the contactor109located at the one end of the cable150extended from the contactor connection terminal TG is allowed to contact a desired location of the vehicle body. Therefore, the location of the ground leakage in the vehicle body can be searched in detail.

In accordance with the ground leakage detector100ofFIG. 3B, the vehicle body ground terminal BG is connected to the vehicle body ground location such as the vehicle body frame4via the charging connector49. This eliminates a need for the operation for bringing the contactor109ofFIG. 3Ainto contact with the vehicle body ground location, which is convenient for the maintenance operator.

[Exemplary Self-Diagnostic Operation of Ground Leakage Detector]

An exemplary self-diagnostic operation of the ground leakage detector100ofFIG. 3Awill be described with reference toFIGS. 6 and 7. An exemplary self-diagnostic operation of the ground leakage detector100ofFIG. 3Bwill not be described, repeatedly.

FIG. 6is a view for explaining the self-diagnostic operation of the ground leakage detector100according to Embodiment 1 of the present invention which is performed by simulating the operation for detecting a ground leakage at the N-side of the battery unit60.FIG. 7is a view for explaining the self-diagnostic operation of the ground leakage detector100according to Embodiment 1 of the present invention which is performed by simulating the operation for detecting a ground leakage at the P-side of the battery unit60. In the examples ofFIGS. 6 and 7, it is supposed that in the electric motorcycle1, the contact of the P-side charging relay51and the contact of the N-side charging relay52which are between the battery unit60and the charging connector49are closed, while in the ground leakage detector100, the connector101is electrically connected to the charging connector49of the electric motorcycle1.

In the example ofFIG. 6, the ground leakage path (represented by the dashed line inFIG. 5) at the N-side of the battery unit60is simulated. Specifically, the switch MSW and the switch SW1are closed. As a result, the coil of the auxiliary relay ASW is excited by the built-in battery107, and the contact of the auxiliary relay ASW is closed. The connection state of the switch SW2is established such that the fixed contact of the switch SW2is connected to one of the movable contacts of the switch SW2which is connected to the N-side connector terminal TN. The switch SW3B is closed such that the ground leakage detector100is electrically connected to the N-side of the battery unit60.

Thereby, there is formed a current path (represented by a bold line inFIG. 6) from the N-side of the battery unit60via the charging connector49, the N-side connector terminal TN, the switch SW3B, the switch SW2, the resistor Rg, the contact of auxiliary relay ASW, and the contactor connection terminal TG. This current path simulates the ground leakage path (represented by the dashed line inFIG. 5) at the N-side of the battery unit60. Also, between the N-side of the battery unit60and the vehicle body frame4maintained at the ground potential, the resistor Rg and the ground leakage detecting resistor Rn are connected in parallel. As compared to the “correct state” in which the switch SW1and the auxiliary relay ASW are open, impedance values between the both ends of the battery unit60and the vehicle body frame4are different. For this reason, currents which are different from those in the “correct state” flow through the ground leakage detecting resistors Rp, Rn, respectively. Accordingly, by confirming the activated state of an LED544and the activated state of a speaker545in the ground leakage detector100, it can be confirmed whether or not the ground leakage detector100is operating correctly.

In the example ofFIG. 7, the ground leakage path (represented by the dashed line inFIG. 4) at the P-side of the battery unit60is simulated. Specifically, the switch MSW and the switch SW1are closed. As a result, the coil of the auxiliary relay ASW is excited by the built-in battery107, and the contact of the auxiliary relay ASW is closed. The connection state of the switch SW2is established such that the fixed contact of the switch SW2is connected to the other of the movable contacts of the switch SW2which is connected to the P-side connector terminal TP. The switch SW3A is closed such that the ground leakage detector100is electrically connected to the P-side of the battery unit60.

Thereby, there is formed a current path (represented by a bold line inFIG. 7) from the P-side of the battery unit60via the charging connector49, the P-side connector terminal TP, the switch SW3A, the switch SW2, the resistor Rg, the contact of the auxiliary relay ASW, and the contactor connection terminal TG. This current path simulates the ground leakage path (represented by the dashed line inFIG. 4) at the P-side of the battery unit60. Also, between the P-side of the battery unit60and the vehicle body frame4maintained at the ground potential, the resistor Rg and the ground leakage detecting resistor Rp are connected in parallel. As compared to the “correct state” in which the switch SW1and the auxiliary relay ASW are opened, impedance values between the both ends of the battery unit60and the vehicle body frame4are different. For this reason, currents which are different from those in the “correct state” flow through the ground leakage detecting resistors Rp, Rn, respectively. Accordingly, by confirming the activated state of the LED544and the activated state of the speaker545in the ground leakage detector100, it can be confirmed whether or not the ground leakage detector100is operating correctly.

In accordance with the above described exemplary operation, the normal ground leakage detecting operation or the operation for determining whether or not the ground leakage detector100is operating correctly, i.e., the self-diagnostic operation, can be selected by using the switch MSW and the switch SW1as desired. This makes it possible to carry out the normal ground leakage detecting operation once it is determined that the ground leakage detector100is operating correctly. In the self-diagnostic operation, instead of actually causing a ground leakage at the P-side or the N-side of the battery unit60, one of the electrodes of the battery unit60and the vehicle body ground location are shorted intentionally, by using the switch SW1, SW2. This makes it possible to carry out the self-diagnostic operation safely and accurately based on the current flowing between the connector connection section and the contactor109.

[Exemplary Operation of in-Vehicle Relays in Ground Leakage Detecting Operation/Self-Diagnostic Operation]

In the above described exemplary operation of the ground leakage detector100, the ground leakage detector100may perform the operation for opening and closing the contact of the P-side charging relay51and the contact of the N-side charging relay52in the electric motorcycle1, via communication with the vehicle body control unit59.

Firstly, the connector101of the ground leakage detector100is electrically connected to the charging connector49of the electric motorcycle1, and thereby the ground leakage detector100is communicatively connected to the vehicle body control unit59via the connector101and the charging connector49. To initiate the ground leakage detecting operation or the self-diagnostic operation, the ground leakage detector100outputs to the vehicle body control unit59commands for activating the P-side charging relay51and the N-side charging relay52to connect the charging connector49and the battery unit60to each other, via the connector101and the charging connector49. Thereby, the contact of the P-side charging relay51and the contact of the N-side charging relay52are closed. Then, the ground leakage detector100closes one of the switch SW3A and the switch SW3B constituting the connector connection section, and thereby is electrically connected to one of the P-side and the N-side of the battery unit60. Then, as described above, the ground leakage detector100detects whether or not there is a ground leakage from one of the P-side and the N-side of the battery unit60to the vehicle body frame4, or confirms (self-diagnoses) the operation in the detection.

After the ground leakage detector100detects whether or not there is a ground leakage, or confirms the operation in the detection, it outputs to the vehicle body control unit59commands for activating the P-side charging relay51and the N-side charging relay52to disconnect the charging connector49and the battery unit60from each other, via the connector101and the charging connector49. Thereby, the contact of the P-side charging relay51and the contact of the N-side charging relay52are opened. Therefore, the battery unit60and the ground leakage detector100are electrically disconnected from each other.

As described above, since the ground leakage detector100causes the P-side charging relay51and the N-side charging relay52in the electric motorcycle1to operate, the electric power stored in the battery unit60can be efficiently used only over a period for which the ground leakage detector100performs the ground leakage detecting operation or the self-diagnostic operation. This makes it possible to lessen consumption of the electric power stored in the battery unit60.

In the present embodiment, the period for which the ground leakage detector100performs the ground leakage detecting operation or the self-diagnostic operation may be, for example, a period before the system in the electric motorcycle1is activated. Specifically, at the activation of the system in the electric motorcycle1, the open/close states of the relays (35to37) placed between the battery unit60and the inverter20are suitably selected to prevent a rush-current from flowing into the inverter20. Or, in another case, at the activation of the system in the electric motorcycle1, the DC/DC converter relay48placed between the battery unit60and the DC/DC converter45is opened or closed.

The ground leakage detector100outputs to the vehicle body control unit59commands for activating the P-side charging relay51and the N-side charging relay52to connect the charging connector49and the battery unit60to each other, via the connector101and the charging connector49, in a period before the time of the activation of the system when the contacts of the relays (35to37,48) are opened or closed. This allows the ground leakage detector100to perform the ground leakage detecting operation or the self-diagnostic operation in the period before the activation of the system in the electric motorcycle1.

In addition, in the present embodiment, when a time for which the ground leakage detector100performs the ground leakage detecting operation or the self-diagnostic operation passes a predetermined threshold time, supplying of the terminal voltage of the battery unit60from the electric motorcycle1to the ground leakage detector100via the charging connector49can be ceased. Specifically, when the time that passes from the initiation of the ground leakage operation, which is counted by the counting section115, reaches the predetermined threshold time, the ground leakage detector100outputs to the vehicle body control unit59commands for activating the P-side charging relay51and the N-side charging relay52to disconnect the charging connector49and the battery unit60from each other, via the connector101and the charging connector49. This makes it possible to carry out the ground leakage operation using the electric power stored in the battery unit60.

Although in the exemplary self-diagnostic operation of the ground leakage detector described with reference toFIGS. 6 and 7, the terminal voltage of the battery unit60mounted in the electric motorcycle1is utilized, the terminal voltage of the built-in battery107mounted in the ground leakage detector100may be utilized.

FIG. 8is a view for explaining a modified example of the self-diagnostic operation ofFIG. 6, which utilizes the terminal voltage of the built-in battery107mounted in the ground leakage detector100.

In the example ofFIG. 8, the ground leakage path (represented by the dashed line inFIG. 4) at the N-side of the battery unit60is simulated. Specifically, the switch MSW and the switch SW1are closed. As a result, the coil of the auxiliary relay ASW is excited by the built-in battery107, and the contact of the auxiliary relay ASW is closed. The connection state of the switch SW2is established such that the fixed contact of the switch SW2is connected to one of the movable contacts of the switch SW2, which is connected to the N-side connector terminal TN. The switch SW3A and the switch SW3B are opened. Thereby, a current path (represented by a bold line inFIG. 8) is formed from the N-side of the built-in battery107to the vehicle body frame4maintained at the ground potential via the switch SW2, the resistor Rg, the contact of the auxiliary relay ASW, the contactor connection terminal TG and the contactor109. This current path simulates the ground leakage path (represented by the dashed line inFIG. 4) at the N-side of the battery unit60. Also, between the N-side of the battery unit60and the vehicle body frame4maintained at the ground potential, the resistor Rg and the ground leakage detecting resistor Rn are connected in parallel. As compared to the “correct state” in which the switch SW1and the auxiliary relay ASW are opened, impedance values between the both ends of the battery unit60and the vehicle body frame4are different. For this reason, currents which are different from those in the “correct state” flow through the ground leakage detecting resistors Rp, Rn, respectively. Accordingly, by confirming the activated state of the LED544and the activated state of the speaker545in the ground leakage detector100, it can be confirmed whether or not the ground leakage detector100is operating correctly.

A modified example of the self-diagnostic operation ofFIG. 7, which utilizes the voltage at the P-side of the built-in battery107mounted in the ground leakage detector100, is similar to the exemplary self-diagnostic operation ofFIG. 8, and therefore will not be described repeatedly.

As described above, in the self-diagnostic process, by utilizing the terminal voltage of the built-in battery107of the ground leakage detector100which is lower than the terminal voltage of the battery unit60of the electric motorcycle1, rather than the terminal voltage of the battery unit60, consumption of the electric power stored in the battery unit60can be lessened. Since the terminal voltage of the built-in battery107of the ground leakage detector100is lower than the terminal voltage of the battery unit60of the electric motorcycle1, it becomes possible to lessen a current flowing when one of the electrodes of the built-in battery107and the vehicle body ground location are shorted via the contactor109in the self-diagnostic process. Thus, safety of the ground leakage detector100can be improved.

Modified Example

As the ground leakage detector100, a fixed ground leakage detector installed on the ground may be used instead of the portable ground leakage detector which can be easily carried by the maintenance operator.

The location which the contactor109contacts in the detection of a ground leakage is not limited to the vehicle body frame4, but may be any vehicle body ground location maintained at the ground potential, in the vehicle body.

The charging connector49of the electric motorcycle1and the connector101of the ground leakage detector100may be a transmission unit and a receiver unit in a non-contact charging method, instead of the method using the exposed connector pins.

In the ground leakage detector100, instead of automatically switching the states of the switches (MSW, SW1, SW2, SW3A, SW3B), by the control unit112, they may be manually switched. In other words, the switches (MSW, SW1, SW2, SW3A, SW3B) are not limited to semiconductor switches or electromagnetic relays, but may be hand-operated switches.

A predetermined termination condition used for terminating detection of a ground leakage may be such that a time that passes from when the detection of a ground leakage is initiated reaches a predetermined threshold, or another condition. For example, the termination condition may be such that the detecting operation of a ground leakage at the P-side and the N-side of the battery unit60is terminated or a ground leakage may be detected at the P-side or the N-side of the battery unit60.

Although a ground leakage at both of the P-side and the N-side of the battery unit60is detectable, a ground leakage only at one of them may be detected. The ground leakage detector may be separate from the outside charger.

The ground leakage detector100may be activated by an outside electric power supply such as a power supply utility, instead of the built-in battery107. For example, an AC/DC converter may convert the AC voltage of the outside electric power supply into the DC voltage and an internal circuit in the ground leakage detector100may operate by this DC voltage. In the embodiment ofFIG. 8, a ground leakage can be sometimes detected without activating the charging relays (51,52). In this case, the command for activating the charging relays (51,52) may not be output to the vehicle body control unit59via the connector101and the charging connector49.

In Embodiment 2 of the present invention, an outside control device including a connector which is electrically connectable to the charging connector of the electric motorcycle provides a control command to the vehicle body control unit via the charging connector, the system in the electric motorcycle is activated in response to this command, and thereby an in-vehicle ground leakage detector performs the operation for detecting whether or not there is a ground leakage. This outside control device has a part or all of the functions of the ground leakage detector100of Embodiment 1, described above, other than those associated with actual detection such as with the ground leakage detecting resistor and those associated with the alarm in the detection of the ground leakage.

The exemplary configuration of the electric system according to Embodiment 2 of the present invention is different from the exemplary configuration of the electric system according to Embodiment 1 shown inFIG. 2, in that the ground leakage detector100electrically connected to the charging connector49is replaced by the outside control device.

FIG. 9is a block diagram showing exemplary circuit configurations of a ground leakage detecting system in the electric motorcycle side and the outside control device side, respectively, according to Embodiment 2 of the present invention. InFIG. 9, for simplified illustration, the charging connector49of the electric motorcycle and the connector of the outside control device are omitted.

Firstly, the configuration of the ground leakage detecting system ofFIG. 9will be described.

In the vehicle body side, an in-vehicle ground leakage detector300includes a P-side power supply terminal P connected to the P-side of the battery unit60via a high-voltage wire301p, an N-side power supply terminal N connected to the N-side of the battery unit60via a high-voltage wire301n, and a ground terminal E connected to the vehicle body frame4via a ground wire302. The in-vehicle ground leakage detector300is configured such that the ground leakage detecting resistors Rp, Rn are connected in series between the P-side power supply terminal P and the N-side power supply terminal N and the connection point of ground leakage detecting resistors Rp, Rn is connected to the ground terminal E. In the in-vehicle ground leakage detector300, in the case of the occurrence of a ground leakage, a current flows through the ground terminal E, and thereby currents which are different from those in the “correct state” flow through the ground leakage detecting resistors Rp, Rn, respectively. The in-vehicle ground leakage detector300determines whether or not there is a ground leakage by detecting a change in the currents. The in-vehicle ground leakage detector300is configured to determine whether or not there is a ground leakage in response to an activation command as a trigger from the vehicle body control unit59, even before the system in the electric motorcycle1is activated, in addition to the normal ground leakage determination after the system in the electric motorcycle1is activated.

An outside control device200includes a control unit260, a pseudo ground leakage circuit210, a built-in battery280, and a switch SW3of the built-in battery280.

The control unit260controls the overall outside control device200. Especially, the control unit260outputs, to the vehicle body control unit59, commands for opening and closing the contact of the P-side charging relay51and the contact of the N-side charging relay52, in the detection of a ground leakage or in a diagnostic process. The control unit260includes a CPU, a DSP, a microcomputer, a logic circuit, or the like. The control unit260may be composed of a plurality of control units which cooperate with each other to perform distributed control.

The pseudo ground leakage circuit210is configured such that an SPST switch SW1, a resistor Rg, and a fixed contact and one of the movable contacts of an SPDT switch SW2are connected in series between the P-side of the battery unit60and the vehicle body frame4. Specifically, one of the fixed contacts of the switch SW1is connected to one end of the resistor Rg, while the other fixed contact of the switch SW1is electrically connected to the vehicle body frame4via a short test wire493. The other end of the resistor Rg is connected to the fixed contact of the switch SW2. The two movable contacts of the switch SW2are connected to the P-side and N-side of the battery unit60, via the charging wires491p,491n, respectively.

When the switch SW3is closed, the built-in battery280supplies a power supply voltage to internal circuits in the outside control device200, such as the control unit260and the pseudo ground leakage circuit210. Note that the terminal voltage of the built-in battery280is set lower than the terminal voltage of the battery unit60.

Next, the exemplary operation of the ground leakage detecting system ofFIG. 9will be described.

In a case where the in-vehicle ground leakage detector300is activated and performs detection of a ground leakage, the outside control device200outputs, to the vehicle body control unit59via the charging connector49, commands for activating the in-vehicle ground leakage detector300and for activating the charging relays (51,52) to connect the charging connector49and the battery unit60to each other, in order to initiate detection of a ground leakage before the system in the electric motorcycle1is activated. In this state, the in-vehicle ground leakage detector300initiates detecting whether or not there is a ground leakage from one of the P-side and the N-side of the battery unit60to the vehicle body frame4.

To utilize the terminal voltage of the battery unit60only for a period when the outside control device200is detecting whether or not there is a ground leakage, the outside control device200may output, to the vehicle body control unit59via the charging connector49, commands for activating the charging relays (51,52) to disconnect the charging connector49and the battery unit60from each other, when a predetermined termination condition is satisfied.

In a case where it is determined (diagnosed) whether or not in-vehicle ground leakage detector300is operating correctly, in the pseudo ground leakage circuit210, the switch SW1is closed and the fixed contact of the switch SW2is connected to one of the movable contacts thereof. This causes the P-side or N-side of the battery unit60and the vehicle body ground location such as the vehicle body frame4to be shorted. At this time, by detecting a change in the currents flowing through the ground leakage detecting resistors Rp, Rn in the in-vehicle ground leakage detector300, it can be determined whether or not the in-vehicle ground leakage detector300is operating correctly. In this case, instead of utilizing the terminal voltage of the battery unit60mounted in the electric motorcycle1, the connector connection section (not shown) of Embodiment 1 may electrically disconnect the battery unit60, and in this state, the terminal voltage of the built-in battery107mounted in the outside control device200may be utilized. This makes it possible to lessen consumption of the electric power stored in the battery unit60.

The ground leakage detector of Embodiment 1 and the control device of Embodiment 2 may be mounted in an outside charger which is electrically connected to the charging connector of the electric motorcycle and charges the battery unit. Hereinafter, such an outside charger will be referred to as a charger with a ground leakage detecting function.

For example,FIG. 10is a view showing an exemplary configuration of the overall system according to Embodiment 3 of the present invention, including a charger with a ground leakage detecting function, incorporating the ground leakage detector according to Embodiment 1 of the present invention.

A charger400with a ground leakage detecting function ofFIG. 10incorporates the ground leakage detector100, and a includes the cable150extended from the ground leakage detector100, the contactor109attached to one end of the cable150, a connector401fittable to the charging connector49, and an attachment plug102connected to a socket (plug-in) of a power supply utility of AC 100V or the like. The charger400with a ground leakage detecting function ofFIG. 10has a structure of ground charging equipment or of ground transmission equipment for non-contact charging. The charger400with a ground leakage detecting function is owned by the user of the electric motorcycle1in a car parking area, placed in a service area called a charging stand or a charging spot, etc.

In accordance with the above described configuration, the connector of the charger400with a ground leakage detecting function which is electrically connectable to the charging connector49of the electric motorcycle1can be efficiently utilized. Therefore, it is not necessary to provide another connector intended for the ground leakage detector100or the outside control device200. This makes it possible to lessen an effect on the configuration of the electric motorcycle1and simplify the configuration of the charger400with a ground leakage detecting function.

Since the charger400with a ground leakage detecting function is configured such that the ground leakage detector100or the outside control device200is integrated with the outside charger, it may notify occurrence of a ground leakage and restrict a charging operation when it determines that there is a ground leakage.

The charger400with a ground leakage detecting function may automatically detect whether or not there is a ground leakage when the charging is initiated or terminated. This makes it possible to automatically confirm whether or not the charging will be or has been performed correctly, when the charger400with a ground leakage detecting function initiates or terminates the charging of the battery unit60. This is convenient to the maintenance operator.

Furthermore, the charger400with a ground leakage detecting function may regularly detect whether or not there is a ground leakage, in a state in which it is electrically connected to the charging connector49for a long period of time. This makes it possible to detect whether or not there is a ground leakage by efficiently utilizing the long period of time when the electric motorcycle1electrically connected to the charging connector49is in storage.

INDUSTRIAL APPLICABILITY

A ground leakage detector the present invention is effectively used to detect whether or not there is a ground leakage in a battery unit mounted in an electric vehicle, especially electric motorcycle.

REFERENCE CHARACTER LIST