Patent Description:
Hitherto, for example, there has been known a charging management device disclosed in Patent Literature <NUM>. This related-art charging management device is installed in a vehicle including an in-vehicle battery to be used as an electric power supply for in-vehicle devices and a solar cell for charging the in-vehicle battery. The solar cell is also capable of being used to charge a rechargeable battery for external devices to be used as an electric power supply to devices external to the vehicle. As a result, for example, when the in-vehicle battery is fully charged, the rechargeable battery for external devices can be charged by the solar cell, enabling the electric power generated by the solar cell installed in the vehicle to be used more efficiently.

Further, hitherto, for example, there has also been known a vehicular power supply control device disclosed in Patent Literature <NUM>. This related-art vehicular power supply control device includes an in-vehicle battery configured to supply electric power to a load group and a solar cell configured to charge the in-vehicle battery using generated electric power. The vehicular power supply control device also includes a storage device configured to store the electric power generated by the solar cell, a switch circuit configured to switch a connection between the solar cell and storage device and the in-vehicle battery on or off, and an operation unit configured to switch the switch circuit on or off.

In addition, hitherto, for example, there has also been known an electric vehicle disclosed in Patent Literature <NUM>. This related-art electric vehicle includes a high-voltage battery configured to drive an electric motor for driving the vehicle, a solar cell, a DC/DC converter for charging configured to supply electric power generated by the solar cell to the high-voltage battery, a charging control electronic control unit (ECU) configured to perform charging control of the high-voltage battery on the DC/DC converter for charging, and a low-voltage power supply DC/DC converter configured to receive a portion of the electric power generated by the solar cell and generate a power supply voltage to be supplied to the charging control ECU.

Still further, hitherto, for example, there has also been known an electric vehicle charging system disclosed in Patent Literature <NUM>. This related-art electric vehicle charging system includes a plurality of solar cell modules formed by wiring solar cell elements together in series so that when sufficient solar light is shone on the solar cell elements, a charging voltage capable of directly charging an auxiliary battery is produced. When the output voltage of the solar cell modules is high, the auxiliary battery is directly charged, and when the output voltage is low, a main battery is charged via a DC/DC converter.

Even still further, hitherto, for example, there has also been known a hybrid vehicle energy regeneration device disclosed in Patent Literature <NUM>. This related-art hybrid vehicle energy regeneration device is configured to store electric power having a large load change generated by regenerative braking of an electric motor during deceleration or electric power generated by a solar cell to an electric dual capacitor. The stored electric power is increased to a predetermined voltage via a charger, and then re-stored in a battery including a lithium ion cell.

Yet even still further, hitherto, for example, there has also been known an electric vehicle control device disclosed in Patent Literature <NUM>. This related-art electric vehicle control device includes a main battery configured to supply electric power to a motor, a first auxiliary battery configured to supply electric power to an electric device in the vehicle, a step-up/step-down transformer configured to step-up and step-down electric power between a drive system circuit and the first auxiliary battery and supply the stepped-up/stepped-down electric power in both directions, a solar panel configured to charge the first auxiliary battery, and a battery control unit configured to control charging and discharging by monitoring remaining levels of the main battery and the first auxiliary battery. Further, in this related-art electric vehicle control device, the battery control unit charges the first auxiliary battery using the solar panel. When the remaining level of the first auxiliary battery reaches a first predetermined value, the battery control unit charges the main battery by increasing the voltage of the electric power of the first auxiliary battery with the step-up/step-down transformer.

In the related-art devices, systems, vehicles, and the like disclosed in Patent Literatures <NUM> to <NUM>, the electric power generated by the solar cell (solar panel) can be supplied to and stored in the main battery configured to supply high-voltage electric power to the motor. The main battery configured to supply electric power to the motor is usually a high-voltage battery. In this case, in order to properly ensure reliability and safety, particularly for a vehicle that is traveling, the main battery is strictly controlled and managed by operating various electronic components and the like in order to execute high-voltage system management, high-voltage battery control, opening/closing control of an electric power opening/closing device (a relay etc.), and power supply control.

Incidentally, when a solar cell is installed in a vehicle (hereinafter referred to as "in-vehicle solar cell"), and the electric power generated by the in-vehicle solar cell used, the maximum amount of generated electric power can be estimated based on the size of the vehicle body (i.e., the installed surface area of the in-vehicle solar cell). Currently, the maximum amount of generated electric power is small, at about a few hundred watts. On the other hand, electric power is also required in order to suitably operate the above-mentioned various electronic components and the like. Consequently, when trying to supply the electric power generated by the in-vehicle solar cell while suitably operating the various electronic components and the like in order to properly ensure reliability and safety while the vehicle is traveling, in some situations the level of electric power required to operate the various electronic components and the like may exceed the generated electric power. In this case, there is an increased likelihood that the generated power cannot be stored in the main battery, and hence no benefit is gained.

In addition, in the related-art devices, systems, vehicles, and the like disclosed in Patent Literatures <NUM> to <NUM>, for example, the charging destination of the electric power generated by the in-vehicle solar cell is managed based on the battery voltage and the state of charge of the main battery supplying high-voltage electric power to the motor. Although this may at first appear to be a rational way to manage charging, issues such as competition with other functions using the generated electric power and competition among the controls can occur. In order to deal with such competition, it is necessary for the system to become more complicated (complex) and for highly complex controls to be performed in order to ensure reliability and safety. This can cause development scale and development costs to increase.

The present invention is directed to solving the above-mentioned problems. It is an object of the present invention to provide a charging control device configured to use an in-vehicle solar cell, the charging control device being modified so that electric power generated by the in-vehicle solar cell can be suitably supplied.

In order to achieve the above-mentioned object, according to one aspect of the present invention which is defined in claim <NUM>, there is provided a charging control device configured to use an in-vehicle solar cell, which is to be applied to the vehicle, the vehicle including: a motor generator configured to generate a driving force and to generate regenerative electric power; a main battery electrically connected to the motor generator, the main battery being configured to supply electric power to the motor generator and to store the regenerative electric power; and a sub-battery configured to supply electric power to various accessory devices mounted on the vehicle, the vehicle being capable of traveling using at least the driving force generated by the motor generator. Examples of such a vehicle that can be adopted include an electric vehicle (EV), a hybrid vehicle (HV), and a plug-in hybrid vehicle (PHV).

Further, the charging control device configured to use an in-vehicle solar cell according to the one aspect of claim <NUM> includes an electric power supply unit and a charging control unit. The electric power supply unit includes the in-vehicle solar cell installed in the vehicle, and is configured to supply electric power generated by the in-vehicle solar cell to at least one of the main battery and the sub-battery. The charging control unit is configured to control charging of at least one of the main battery and the sub-battery using the electric power generated by the in-vehicle solar cell and supplied from the electric power supply unit.

A feature of the charging control device configured to use an in-vehicle solar cell according to the one aspect of claim <NUM> resides in that the charging control unit is configured to, when the vehicle is traveling, prevent the electric power generated by the in-vehicle solar cell from being supplied from the electric power supply unit to the main battery. Note that, in this case, the charging control unit includes traveling determination means for determining whether or not the vehicle is traveling and disconnecting means for disconnecting a connection between the electric power supply unit and the main battery. When it is determined by the traveling determination means that the vehicle is traveling, the disconnecting means can prevent the electric power generated by the in-vehicle solar cell from being supplied from the electric power supply unit to the main battery by disconnecting the connection between the electric power supply unit and the main battery.

According to this, when the vehicle is traveling, that is, when there is a possibility that the electric power of the main battery is being supplied to the motor generator, the electric power generated by the in-vehicle solar cell can be prevented from being supplied to the main battery directly from the in-vehicle solar cell, or via a storage device configured to temporarily store the generated electric power. This eliminates the need to execute more complex controls without having an effect on how the main battery is managed based on, for example, high-voltage system management, high-voltage battery control, opening/closing control of an electric power opening/closing device (a relay etc.), and power supply control, namely, by avoiding competition among the controls and the like. Therefore, an increase in development scale and in development costs can be suppressed, and the electric power generated by the in-vehicle solar cell can be appropriately used.

In this case, the charging control unit can supply the electric power generated by the in-vehicle solar cell from the electric power supply unit to the sub-battery when the vehicle is traveling. Note that, in this case, the charging control unit may include supply means for supplying or disconnecting the electric power generated by the in-vehicle solar cell from the electric power supply unit to the sub-battery. When it is determined by the traveling determination means that the vehicle is traveling, the supply means can supply the electric power generated by the in-vehicle solar cell from the electric power supply unit to the sub-battery. Consequently, when the vehicle is traveling, the electric power generated by the in-vehicle solar cell can be stored (accumulated) in the low-voltage sub-battery without executing the above-mentioned highly complex management operations and controls on the main battery, which enables the electric power generated by the in-vehicle solar cell to be used in an efficient manner.

Further, in those cases, the electric power supply unit may include a low-voltage battery configured to temporarily store the electric power generated by the in-vehicle solar cell, and the charging control unit may be configured to at least, when the vehicle is traveling, supply the electric power generated by the in-vehicle solar cell and temporarily stored in the low-voltage battery to the sub-battery.

According to this, the electric power generated by the in-vehicle solar cell can be temporarily stored in the low-voltage battery, and when the vehicle is traveling, the generated electric power can be supplied to the sub-battery. Further, by temporarily storing the electric power generated by the in-vehicle solar cell in the low-voltage battery in this manner, when the vehicle is not traveling, for example, when the vehicle is stopping or parking, not only can the electric power be supplied to the sub-battery, but the electric power can also be supplied to the main battery. Consequently, the electric power generated by the in-vehicle solar cell can be used in an efficient manner.

Further, in those cases, the charging control unit may be configured to permit, when the vehicle is not traveling, the electric power generated by the in-vehicle solar cell to be supplied from the electric power supply unit to the main battery.

According to this, when the vehicle is not traveling, for example, when the vehicle is stopping or parking, the electric power generated by the in-vehicle solar cell can be supplied from the electric power supply unit to the main battery. In this case, because the vehicle is not traveling, the electric power generated by the in-vehicle solar cell can be supplied to and stored in the main battery based on the same charging controls as for an ordinary EV, HV, or PHV, for example. Therefore, the main battery can be charged using the generated electric power without executing separate complex controls.

In this case, the charging control unit may be configured to permit, when a level of the electric power generated by the in-vehicle solar cell is more than a predetermined electric power level set in advance, the electric power generated by the in-vehicle solar cell to be supplied from the electric power supply unit to the main battery. In this case, more specifically, for example, it is preferred that the predetermined electric power level be set based on a level of electric power consumed by various electronic components operating as a result of the charging control of the main battery.

According to those, when the level of electric power generated by the in-vehicle solar cell is more than the level of electric power consumed by the various electronic components operating when charging the main battery on which high-voltage management and control are being strictly carried out, the electric power generated by the in-vehicle solar cell can be supplied to and stored in the main battery. Consequently, when charging the main battery using the electric power generated by the in-vehicle solar cell, a situation in which the main battery cannot be charged because the supplied electric power is being consumed by the operation of the various electronic components can be prevented. Further, when the level of electric power generated by the in-vehicle solar cell is more than the level of electric power consumed by the various electronic components, the operating frequency of the various electronic components can be appropriately reduced by quickly executing the charging of the main battery. As a result, the amount of wasted electric power that is consumed without being stored in the main battery can be suppressed, with the result that the electric power generated by the in-vehicle solar cell can be used in a more efficient manner.

Further, another feature of the charging control device configured to use an in-vehicle solar cell according to the one embodiment of the present invention also resides in that: the electric power supply unit is further configured to supply, when the vehicle is not traveling, electric power supplied externally from the vehicle to at least the main battery; and the charging control unit is configured to supply the electric power generated by the in-vehicle solar cell to the main battery or the sub-battery based on a supply state of the external electric power in the electric power supply unit. Note that, in this case, the electric power supply unit may include external electric power supply means for supplying the electric power supplied externally from the vehicle to at least the main battery.

According to this, when the vehicle is not traveling, the electric power generated by the in-vehicle solar cell can be supplied to the main battery or the sub-battery depending on the supply state of the external electric power to at least the main battery, for example, depending on whether electric power is being supplied (charging) because the main battery is not fully charged or whether the supply electric power is disconnected because the main battery is fully charged (charging completed). Consequently, for example, the supply state of the external electric power can be determined using the same control as for an ordinary EV or PHV. Therefore, the electric power generated by the in-vehicle solar cell can be used in a more efficient manner without executing complex controls.

In this case, more specifically, the charging control unit may be configured to supply, when the electric power supply unit is charging the main battery by supplying the external electric power to the main battery, the electric power generated by the in-vehicle solar cell to the main battery. According to this, the electric power required in order to charge the battery can be met by the external electric power and the electric power generated by the in-vehicle solar cell. Therefore, the amount of electric power bought from, for example, the commercial power supply as the external electric power can be reduced by the amount of electric power that is generated by the in-vehicle solar cell, allowing the costs incurred by charging to be decreased.

Further, of the electric power stored in the main battery, the ratio of the electric power generated by the in-vehicle solar cell, namely, the ratio of renewable energy, can be increased. As a result, for example, depending on the region in which the vehicle is traveling, fuel consumption (electricity consumption) may be calculated based on the ratio of the electric power generated by the in-vehicle solar cell, and from an environmental protection perspective, the driver or an occupant may receive preferential treatment due to improved fuel consumption (electricity consumption).

Further, in those cases, the charging control unit may be configured to supply, when the charging of the main battery is complete, the electric power generated by the in-vehicle solar cell to the sub-battery. According to this, dark current consumed by the various accessory devices that are being operated can be suitably compensated for with the electric power supplied from the sub-battery. Therefore, the sub-battery can be prevented from becoming "dead" in advance. Further, by changing the supply destination (charging destination) of the electric power generated by the in-vehicle solar cell to the sub-battery when the charging of the main battery is complete, overcharging of the main battery can be avoided, with the result that the main battery can be suitably protected.

Further, still another feature of the charging control device configured to use an in-vehicle solar cell according to the one embodiment of the present invention also resides in that the charging control unit is configured to supply, when the vehicle is not traveling, and when the various accessory devices are operating based on an operation request from an occupant in the vehicle, the electric power generated by the in-vehicle solar cell from the electric power supply unit to the sub-battery.

According to this, the supply destination (charging destination) of the electric power generated by the in-vehicle solar cell can be selected based on the wishes of the occupant in the vehicle. Consequently, for example, even when the vehicle is not traveling, and hence normally the electric power generated by the in-vehicle solar cell is supplied to the main battery based on the state of charge, if the occupant requests operation of the various accessory devices (specifically, such as by switching the ignition to the accessory position), the sub-battery can be preferentially selected as the charging destination based on the occupant's wishes. Therefore, by supplying the electric power generated by the in-vehicle solar cell to the sub-battery, even when the various accessory devices are being operated, the sub-battery can be suitably prevented from becoming "dead".

A charging control device (hereinafter simply referred to as "the device") using an in-vehicle solar cell according to one embodiment of the present invention is now described with reference to the drawings.

<FIG> is a block diagram for illustrating a configuration of a vehicle <NUM> to which the device can be applied. Examples of vehicles that may be used as the vehicle <NUM> to which the device can be applied include an electric vehicle (EV), which includes a motor generator driven by electric power from an installed main battery and which charges the main battery using regenerative electric power and an external power supply supplied from a charging station and the like, a hybrid vehicle (HV) including a motor generator and an engine, and a plug-in hybrid vehicle (PHV) capable of charging a main battery by using an external power supply additionally compared with a hybrid vehicle (HV). Note that, in this embodiment, a description is given with an example in which the vehicle <NUM> is a plug-in hybrid vehicle (PHV).

As illustrated in <FIG>, the vehicle <NUM> according to this embodiment includes, in addition to a driving force generation unit <NUM>, an electric power supply unit <NUM> and a charging controller <NUM> as a charging control unit included in the device. The driving force generation unit <NUM> includes an engine <NUM>, a motive power dividing mechanism <NUM>, motor generators <NUM> and <NUM>, a transmission gear <NUM>, a drive axle <NUM>, a power controller unit (PCU) <NUM>, a main battery <NUM>, and a sub-battery <NUM>. The engine <NUM> is configured to output motive power by combustion of a hydrocarbon-based fuel, such as gasoline or diesel fuel. In the vehicle <NUM>, the motive power (kinetic energy) output by the engine <NUM> drives, via the motive power dividing mechanism <NUM>, the transmission gear <NUM>, which is configured to transmit motive power to the drive axle <NUM> (wheels).

The motive power dividing mechanism <NUM> is coupled to the engine <NUM>, the motor generator <NUM> (<NUM>), and the transmission gear <NUM>, and distributes motive power among those units. As the motive power dividing mechanism <NUM>, for example, a planetary gear having three axes of rotation, from a sun gear, a planetary carrier, and a ring gear, may be employed. The motor generator <NUM> is connected to the sun gear. The engine <NUM> is connected to the carrier. The drive axle <NUM> and the motor generator <NUM> are connected to the ring gear via the transmission gear <NUM>.

The motor generators <NUM> and <NUM> are three-phase synchronous generator-motors controlled by the PCU <NUM>. When electric power from the main battery <NUM> is supplied, the motor generators <NUM> and <NUM> function as electric motors, and when external (e.g., from the engine <NUM>) motive power (kinetic energy) is transmitted, the motor generators <NUM> and <NUM> function as electric generators. Specifically, the motor generator <NUM> functions as an electric generator when motive power (kinetic energy) from the engine <NUM> that has been divided by the motive power dividing mechanism <NUM> is transmitted, and the motor generator <NUM> also functions as a starter motor capable of starting the engine <NUM>. The motor generator <NUM> functions as an electric motor (a motive power source) for driving the transmission gear <NUM> configured to transmit a driving force to the drive axle <NUM>(wheels). Note that, in this embodiment, although the motor generator <NUM> functions as an electric generator and the motor generator <NUM> functions as an electric motor, obviously the motor generator <NUM> may function as an electric generator and the motor generator <NUM> may function as an electric motor, or, the motor generators <NUM> and <NUM> may both function as electric generators or electric motors.

The main battery <NUM>, which is a so-called high-voltage power supply, is electrically connected to the motor generators <NUM> and <NUM> via the PCU <NUM>. The sub-battery <NUM>, which is a so-called low-voltage power supply as an auxiliary battery, is electrically connected to various electronic control units including the charging controller <NUM> installed in the vehicle <NUM>, and various accessory devices installed in the vehicle <NUM>.

As illustrated in <FIG>, the electric power supply unit <NUM> included in the device includes an in-vehicle solar cell <NUM>, a low-voltage battery <NUM>, a solar charger <NUM>, and a plug-in charger <NUM>. The in-vehicle solar cell <NUM>, which is mounted on, for example, the roof of the vehicle <NUM>, is configured to convert solar energy into electrical energy. Note that, in the following description, the electric power generated by the in-vehicle solar cell <NUM> is also referred to as "electric power generated from solar light". The low-voltage battery <NUM> is configured to temporarily store the low-voltage electric power generated by the in-vehicle solar cell <NUM>, and, as described later, output electric power to the main battery <NUM> and/or the sub-battery <NUM>. Therefore, the low-voltage battery <NUM> is electrically connected to the in-vehicle solar cell <NUM> via a fuse, a blocking diode, and the like (not shown).

The solar charger <NUM> is configured to supply the electric power temporarily stored in the low-voltage battery <NUM> to the main battery <NUM> and/or the sub-battery <NUM>. Therefore, the solar charger <NUM> includes a charging control circuit 23a for supplying the electric power temporarily stored (accumulated) in the low-voltage battery <NUM>, namely, the electric power generated from solar light, to the main battery <NUM> and/or the sub-battery <NUM>. Although not shown, the charging control circuit 23a includes a high-voltage charging DC/DC converter configured to raise (pump up) the low-voltage electric power (electric power generated from solar light) stored (accumulated) in the low-voltage battery <NUM> to a high voltage, and supply that high-voltage electric power to the main battery <NUM>, and a low-voltage charging DC/DC converter configured to supply low-voltage electric power stored in the low-voltage battery <NUM> to the sub-battery <NUM>.

The plug-in charger <NUM> is, for example, configured to be electrically connected to a charging station and the like installed in a person's home or at a public facility via a cable or in a contactless manner, to convert alternating current supplied as an external power supply (specifically, a commercial power supply) into direct current, and supply that direct current to charge the main battery <NUM> and/or the sub-battery <NUM>. Therefore, the plug-in charger <NUM> includes, for example, an electric power circuit including a smoothing capacitor, a voltage converter, an inverter circuit, and the like (not shown).

Further, as illustrated in <FIG>, the electric power supply unit <NUM> includes a system main relay <NUM> arranged on a driving electric power supply path linking the main battery <NUM> and the PCU <NUM> (namely, motor generators <NUM> and <NUM>). The system main relay <NUM> is arranged between a high-voltage power supply line PML1 on the main battery <NUM> side and a high-voltage power supply line PML2 on the PCU <NUM> side. Based on an opening/closing operation, the system main relay <NUM> selectively switches between connection and disconnection between the PCU <NUM> (namely, motor generators <NUM> and <NUM>), and the main battery <NUM>. In addition, as illustrated in <FIG>, the electric power supply unit <NUM> includes a DC/DC converter <NUM> arranged between a high-voltage power supply line PML3, which is connected to the high-voltage power supply line PML2 on the PCU <NUM> side, and the sub-battery <NUM>.

The DC/DC converter <NUM> is configured to convert (reduce) the voltage of the high-voltage power supply of the high-voltage power supply line PML3, which is on an upstream side, to a low voltage, and supply the low-voltage power supply to the sub-battery <NUM> via a low-voltage power supply line PTL1, which is on a downstream side. Note that, as illustrated in <FIG>, the solar charger <NUM> and the sub-battery <NUM> are connected to each other via a low-voltage power supply line PTL2, and the plug-in charger <NUM> and the sub-battery <NUM> and connected to each other via a low-voltage power supply line PTL3. Further, in <FIG> and <FIG> to <FIG> described below, the power supply lines along which the high-voltage power supply flows are represented by bold, solid lines, and the power supply lines along which the low-voltage power supply flows are represented by double lines.

In addition, as illustrated in <FIG>, the electric power supply unit <NUM> includes a charging relay <NUM> as disconnecting means arranged on the charging electric power supply path linking the solar charger <NUM> and the plug-in charger <NUM> with the main battery <NUM>. The charging relay <NUM> is arranged between a charging power supply line PUL1 on the main battery <NUM> side and a charging power supply line PUL2 on the plug-in charger <NUM> (solar charger <NUM>) side. In this case, the solar charger <NUM> is electrically connected to the charging power supply line PUL2 via a charging power supply line PUL3. Further, although the plug-in charger <NUM> is directly connected to the charging power supply line PUL2, the plug-in charger <NUM> is electrically connected to the charging power supply line PUL3 via a charging power supply line PUL4. Note that, a blocking diode for preventing current from flowing from the charging power supply line PUL2 side to the solar charger <NUM> side is arranged on the charging power supply line PUL3, and a blocking diode for preventing current from flowing from the charging power supply line PUL3 side to the plug-in charger <NUM> side is arranged on the charging power supply line PUL4.

As illustrated in <FIG>, the charging controller <NUM> as the charging control unit included in the device includes a solar ECU <NUM> and a battery ECU <NUM>. The solar ECU <NUM> is a microcomputer including a central processing unit (CPU), a read-only memory (ROM), a random-access memory (RAM), and the like as main constituent components. The solar ECU <NUM> is configured to control charging of (storing of electric power in) the low-voltage battery <NUM> with the electric power generated by the in-vehicle solar cell <NUM> and operation of the solar charger <NUM> in an integrated manner.

The battery ECU <NUM> is also a microcomputer including a CPU, a ROM, a RAM, and the like as its main constituent components. The battery ECU <NUM> is configured to control charging of the main battery <NUM> in an integrated manner by monitoring the charging state of the main battery <NUM>, and controlling operation of the charging relay <NUM>. For this purpose, a known charging sensor 32a is connected to the battery ECU <NUM>. The charging sensor 32a, which is mounted in the main battery <NUM>, is configured to detect a state of charge (SOC) of the main battery <NUM>, and output a signal representing the SOC to the battery ECU <NUM>. As a result, the battery ECU <NUM> manages and controls charging of the main battery <NUM> based on a charging state, namely, the SOC, of the main battery <NUM> detected by the charging sensor 32a.

Further, as illustrated in <FIG>, the charging controller <NUM> includes a hybrid ECU <NUM>. The hybrid ECU <NUM>, which operates the engine <NUM> and the motor generators <NUM> and <NUM> in cooperation with one another, is configured to control the driving force for enabling the vehicle <NUM> to travel. Therefore, the hybrid ECU <NUM> is also a microcomputer including a CPU, a ROM, a RAM, and the like as main constituent components, and is configured to control a switching operation of the system main relay <NUM> when the vehicle <NUM> is traveling and during charging of the vehicle <NUM>. In addition, the charging controller <NUM> also includes a plug-in ECU <NUM>. The plug-in ECU <NUM> is configured to control operation of the plug-in charger <NUM> in an integrated manner. For this purpose, the plug-in ECU <NUM> is also a microcomputer including a CPU, a ROM, a RAM, and the like as main constituent components.

The hybrid ECU <NUM>, in cooperation with at least the battery ECU <NUM>, strictly executes high-voltage system management and high-voltage battery control relating to the main battery <NUM>, opening/closing operation management of the system main relay <NUM> and the charging relay <NUM>, the power supply controls required for the vehicle <NUM> to travel, and the like. Therefore, various electronic components are installed around the main battery <NUM> in the vehicle <NUM>. Note that, those electronic components are not shown in <FIG> because those components are well known in the art. Executing the above-mentioned various management and control operations with the various electronic components ensures the reliability and safety of the vehicle <NUM> in which the high-voltage battery main battery <NUM> is mounted.

Further, as illustrated in <FIG>, the solar ECU <NUM>, the battery ECU <NUM>, the hybrid ECU <NUM>, and the plug-in ECU <NUM> are capable of communicating to/from each other via a communication line (e.g., a CAN communication line) built in the vehicle <NUM>. In particular, as illustrated in <FIG>, the solar ECU <NUM> and the hybrid ECU <NUM> are directly connected to each other via a verification ECU <NUM> (a microcomputer). As a result, the solar ECU <NUM> can communicate to/from the hybrid ECU <NUM> after the solar ECU <NUM> has been verified by the verification ECU <NUM>. Consequently, as described later, this enables various signals (start signals etc.) to be directly supplied.

Next, the operations of the charging controller <NUM> included in the device are described in more detail. First, the operations performed when the vehicle <NUM> is traveling are described. When an ignition (I/G) (not shown) is turned on by the driver, and the hybrid ECU <NUM> has switched the system main relay <NUM> to a closed state (connected state), the vehicle <NUM> is in a so-called "Ready ON" state in which the vehicle <NUM> is capable of traveling based on the motive power of at least the motor generator <NUM>. Note that, for example, when the SOC of the main battery <NUM> being managed by the battery ECU <NUM> is a predetermined SOC or more, the hybrid ECU <NUM> switches the system main relay <NUM> to a closed state (connected state), namely, the vehicle <NUM> is in a "Ready ON" state.

In other words, in the "Ready ON" state, the high-voltage power supply line PML1 on the main battery <NUM> side and the high-voltage power supply line PML2 on the PCU <NUM> side are maintained in a state in which the high-voltage power supply line PML1 and the high-voltage power supply line PML2 are connected to each other by various electronic components, including the system main relay <NUM>. Consequently, while the vehicle <NUM> is traveling, in cooperation with the battery ECU <NUM>, the hybrid ECU <NUM> supplies high-voltage electric power from the main battery <NUM> to the motor generator <NUM> (<NUM>) via the PCU <NUM> by controlling the power supply in a known manner. Consequently, the motor generator <NUM> (<NUM>) generates a predetermined driving force based on operation of the accelerator by the driver, and transmits the driving force to the drive axle <NUM> (wheels) via the transmission gear <NUM>.

Further, when the vehicle <NUM> is traveling, or more specifically, when the vehicle <NUM> is in a "Ready ON" state, the hybrid ECU <NUM> switches the charging relay <NUM> to an open state (disconnected state) with respect to the battery ECU <NUM>. As a result, the charging power supply line PUL1 on the main battery <NUM> side and the charging power supply line PUL2 on the plug-in charger <NUM> (solar charger <NUM>) side are maintained in a state in which the charging power supply line PUL1 and the charging power supply line PUL2 are disconnected from each other by various electronic components, including the charging relay <NUM>. In other words, while the vehicle <NUM> is traveling, the main battery <NUM> is maintained in a state in which the main battery <NUM> is completely (absolutely) disconnected from the solar charger <NUM> and the plug-in charger <NUM> based on known high-voltage system management and high-voltage battery management operations.

As a result, while the vehicle <NUM> is traveling, electric power is prevented from being supplied from the solar charger <NUM>, thereby preventing the main battery <NUM> from being charged. Note that, while the vehicle <NUM> is traveling, because an electrical connection is not established between the plug-in charger <NUM> and the charging station arranged externally to the vehicle <NUM>, the main battery <NUM> is not charged using an external power supply.

In a state in which the traveling vehicle <NUM> is slowing down (e.g., the driver has pressed the brake), the hybrid ECU <NUM> performs a regeneration control with the motor generator <NUM> (<NUM>) via the PCU <NUM> to convert the kinetic energy of the vehicle <NUM> into recovered electrical energy. In other words, when the vehicle <NUM> is slowing down, based on regeneration control performed by the hybrid ECU <NUM> and the PCU <NUM>, the motor generator <NUM> (<NUM>) converts the kinetic energy transmitted from the drive axle <NUM> (wheels) via the transmission gear <NUM> and the motive power dividing mechanism <NUM> into electrical energy.

The PCU <NUM> outputs the converted electrical energy, namely, the recovered electric power, to the high-voltage power supply line PML2 as regenerated electric power. At this point, because the vehicle <NUM> is in a "Ready ON" state and the system main relay <NUM> is maintained in a closed state (connected state), the high-voltage power supply line PML2 is connected to the high-voltage power supply line PML1 on the main battery <NUM> side. Consequently, when regenerated electric power produced by the regeneration control is output, the voltage of the regenerated electric power is increased by various electronic components (not shown) (specifically, a DC/DC converter etc.) and the resultant electric power is stored in the main battery <NUM>. Alternatively, the voltage of the regenerated electric power produced by the regeneration control and output to the high-voltage power supply line PML3 is reduced by the DC/DC converter <NUM>. The resultant electric power is output to the low-voltage power supply line PTL1, and stored in the sub-battery <NUM>.

Next, charging control of the main battery <NUM> or the sub-battery <NUM> of the vehicle <NUM> by the charging controller <NUM> is described in various different situations.

As described above, when the vehicle <NUM> is traveling, the battery ECU <NUM> of the charging controller <NUM> maintains the charging relay <NUM> arranged between the main battery <NUM> and the solar charger <NUM> in an open state (disconnected state) in order to give priority to reliability and safety in view of the fact that a high-voltage power supply is being handled. However, when the vehicle <NUM> is traveling, if the in-vehicle solar cell <NUM> is in a state capable of generating electric power, specifically, during daytime on a fine day, the in-vehicle solar cell <NUM> generates electric power by converting solar energy into electrical energy. In this case, the solar ECU <NUM> of the charging controller <NUM> temporarily stores the electric power generated by the in-vehicle solar cell <NUM>, namely, electric power generated from solar light, in the low-voltage battery <NUM>.

When the vehicle <NUM> is traveling, specifically, as illustrated in <FIG>, when the ignition (I/G) in the vehicle <NUM> is in an ON state, and, the vehicle <NUM> is in a "Ready ON" state, the solar ECU <NUM> selects the sub-battery <NUM> as the charging destination, and supplies the electric power generated from solar light temporarily stored in the low-voltage battery <NUM> to the sub-battery <NUM>. In other words, the solar ECU <NUM> uses a low-voltage charging DC/DC converter in the charging control circuit 23a of the solar charger <NUM> to transform and rectify the electric power generated from solar light into a predetermined voltage, and then supplies and stores the electric power generated from solar light in the sub-battery <NUM> via the low-voltage power supply line PTL2. Note that, in this case, obviously the solar charger <NUM> (solar ECU <NUM>) supplies the electric power generated from solar light to the sub-battery <NUM> so that the sub-battery <NUM> is not overcharged, based on an SOC detected by a charging sensor (not shown) included in the sub-battery <NUM>.

Thus, when the vehicle <NUM> is traveling, because the solar ECU <NUM> selects the sub-battery <NUM> as the charging destination, only a low-voltage power supply is handled in the vehicle <NUM> without the voltage of the electric power generated from solar light being substantially increased. In other words, when the vehicle <NUM> is traveling, if the main battery <NUM> is selected as the charging destination, a high-voltage power supply having a significantly increased voltage that has been obtained from the electric power generated from solar light needs to be handled in the vehicle <NUM>. When handling the electric power generated from solar light as a high-voltage power supply, there is an inevitable increase in complexity in order to avoid competition among the system management and charging control operations required to ensure the reliability and safety of the high-voltage battery main battery <NUM>. In contrast, when the sub-battery <NUM> is selected as the charging destination, a low-voltage power supply can be handled in the same manner as in EVs, HVs, PHVs, and traditional vehicles, and as a result, the system and charging control can be simplified.

For example, when it is determined based on a detected vehicle speed and the like that the vehicle <NUM> is stopping or parking, there is no need to supply a high-voltage power supply to the motor generator <NUM>, and hence the hybrid ECU <NUM> switches the system main relay <NUM> to an open state (disconnected state). When the hybrid ECU <NUM> switches the system main relay <NUM> to an open state (disconnected state) in this manner, the vehicle <NUM> is, at the very least, in a state in which the vehicle <NUM> is not traveling based on a driving force from the motor generator <NUM>, namely, is in a "Ready OFF" state. In this "Ready OFF" state, the charging controller <NUM> uses a different charging destination when the ignition (I/G) is in an on state from that when the ignition (I/G) is in an off state. This operation is now described in more detail.

When the vehicle <NUM> is in a "Ready OFF" state, as illustrated in <FIG>, the battery ECU <NUM> may switch the charging relay <NUM> to a closed state (connected state). As a result, when the driver has switched the ignition (I/G) to an off state and the vehicle <NUM> is stopping or parking, namely, when the vehicle <NUM> is not traveling, the electric power generated from solar light that is temporarily stored in the low-voltage battery <NUM> may be supplied to and stored in the main battery <NUM>. This charging operation of the main battery <NUM> is now described in more detail.

As shown in <FIG>, when the ignition (I/G) in the vehicle <NUM> is in an off state, and, the vehicle <NUM> is in a "Ready OFF" state, the solar ECU <NUM> selects the main battery <NUM>, which is in a not-fully charged state, as the charging destination, and supplies the electric power generated from solar light temporarily stored in the low-voltage battery <NUM> to the main battery <NUM>. Note that, in this case, the plug-in charger <NUM> may not be electrically connected to a charging station. In other words, this operation may be carried out on condition that there are no means for supplying electric power to the main battery <NUM> other than the solar charger <NUM>.

As described above, various electronic components, including the system main relay <NUM>, the charging relay <NUM>, and the like, are arranged in the vicinity of the main battery <NUM> in order to handle the high-voltage power supply safely. Further, in order to monitor the state of the main battery <NUM> and to control charging of the main battery <NUM>, the battery ECU <NUM>, the hybrid ECU <NUM>, the plug-in ECU <NUM>, the verification ECU <NUM>, and the like need to be made to operate. In addition, in order to operate the various electronic components and the various ECUs, a predetermined operational electric power is required.

Therefore, when the electric power generated from solar light is to be supplied to and stored in the main battery <NUM>, the solar ECU <NUM> executes charging control when the level of electric power temporarily stored in the low-voltage battery <NUM> is at least a predetermined operational electric power level or more. If the level of the electric power generated from solar light stored in the low-voltage battery <NUM> is the predetermined operational electric power level or more, the electric power generated from solar light can be stored in the main battery <NUM> even if electric power is consumed from operation of the above-mentioned various electronic components and various ECUs.

Specifically, the solar ECU <NUM> determines whether or not the amount of electric power generated from solar light generated by the in-vehicle solar cell <NUM> and temporarily (provisionally) stored in the low-voltage battery <NUM>, namely, the SOC of the low-voltage battery <NUM>, is higher than an SOC corresponding to the above-mentioned predetermined operational electric power. By charging the main battery <NUM> each time the SOC of the low-voltage battery <NUM> is higher than the SOC corresponding to the predetermined operational electric power, the frequency with which the various below-mentioned electronic components and the various ECUs are operated (started up) can be reduced. As a result, the electric power consumed each time the various electronic components and the various ECUs are operated (started up), namely, the electric power consumed by operating the devices required to charge the main battery <NUM>, can be reduced, with the result that the electric power generated from solar light can be efficiently stored in the main battery <NUM>.

After the electric power generated from solar light has been stored until the SOC of the low-voltage battery <NUM> is higher than the SOC corresponding to the predetermined operational electric power, as illustrated in <FIG>, verification is performed by the verification ECU <NUM>, and the solar ECU <NUM> outputs startup signals to start the hybrid ECU <NUM> and the battery ECU <NUM> and the plug-in ECU <NUM> that operate in cooperation with the hybrid ECU <NUM> in order to safely charge the main battery <NUM>. The hybrid ECU <NUM>, which has been started by the output startup signal, maintains the system main relay <NUM> in an open state (disconnected state). The battery ECU <NUM> started by the output startup signal switches the charging relay <NUM> from an open state (disconnected state) to a closed state (connected state), thereby connecting the charging power supply line PUL1 on the main battery <NUM> side and the charging power supply line PUL2 on the solar charger <NUM> side. The plug-in ECU <NUM> started by the output startup signal controls an electric power (current) supply path in a manner that allows, as described below, an external power supply to be supplied.

In particular, when the charging relay <NUM> is switched by the battery ECU <NUM> to a closed state (connected state), the solar ECU <NUM> raises (pumps up) and rectifies the low-voltage electric power temporarily stored in the low-voltage battery <NUM> with a high-voltage charging DC/DC converter in the charging control circuit 23a of the solar charger <NUM> to a predetermined voltage in a short period of time, and supplies the electric power whose voltage has been converted into a high voltage to the main battery <NUM> via the charging power supply line PUL3 and the charging power supply line PUL2. As a result, the battery ECU <NUM> can, by controlling charging in a known manner, store the electric power (electric power generated from solar light) supplied from the solar charger <NUM> (solar ECU <NUM>) in the main battery <NUM>.

Further, in this case, electric power in the sub-battery <NUM> is consumed in order to start up the various electronic components and the various ECUs. As a result, the solar ECU <NUM> rectifies the low-voltage electric power temporarily stored in the low-voltage battery <NUM> with the low-voltage charging DC/DC converter in the charging control circuit 23a of the solar charger <NUM>, and supplies the electric power to the sub-battery <NUM> via the low-voltage power supply line PTL2, only while the voltage of the electric power is being raised (pumped up) as described above. Consequently, the state of charge of the sub-battery <NUM> can be made to recover, thereby preventing the sub-battery <NUM> from becoming "dead".

In cases such as, for example, when the driver or an occupant in the vehicle <NUM> wants to use an accessory device that can be operated by switching the ignition (I/G) to an on state, or when the engine <NUM> did not start successfully, the vehicle <NUM> is not traveling, and as shown in <FIG>, the ignition (I/G) is in an on state, and, the vehicle <NUM> is in an "Ready OFF" state. In this case, because the load on the sub-battery <NUM> increases as a result of the operation of the accessory device in accordance with the wishes (will) of the driver or the occupant, the solar ECU <NUM> selects the sub-battery <NUM> as the charging destination, and supplies the electric power generated from solar light temporarily stored in the low-voltage battery <NUM> to the sub-battery <NUM>.

In other words, the solar ECU <NUM> uses the low-voltage charging DC/DC converter in the charging control circuit 23a of the solar charger <NUM> to transform and rectify the electric power generated from solar light into a predetermined voltage, and then supplies and stores this electric power in the sub-battery <NUM> via the low-voltage power supply line PTL2. Note that, in this case too, obviously the solar charger <NUM> (solar ECU <NUM>) supplies the electric power generated from solar light to the sub-battery <NUM> so that the sub-battery <NUM> is not overcharged, based on an SOC detected by a charging sensor (not shown) included in the sub-battery <NUM>.

Thus, in a situation in which the load on the sub-battery <NUM> is increasing, namely, in a situation in which consumption of the electric power stored in the sub-battery <NUM> is increasing, the selection by the solar ECU <NUM> of the sub-battery <NUM> as the charging destination allows the electric power generated from solar light to be suitably supplied. As a result, the sub-battery <NUM> can be suitably prevented from becoming "dead". Note that, because the electric power supplied to the sub-battery <NUM> has a low voltage, as described above, a low-voltage power supply can be handled in the same manner as for traditional vehicles other than EVs, HVs, and PHVs, and as a result, the system and charging control can be simplified.

In a situation in which the ignition (I/G) is in an off state, for example, a situation in which the vehicle <NUM> is parked at the driver's home, the driver may perform charging using an external power supply, or so-called "plug-in charging". In plug-in charging, the solar ECU <NUM> changes the charging destination of the electric power generated from solar light to any one of the main battery <NUM> or the sub-battery <NUM> based on the supply state of the electric power being supplied from the external power supply to the main battery <NUM> by the plug-in ECU <NUM>. Such cases are now described in more detail.

When the plug-in charger <NUM> of the vehicle <NUM> and a charging station are electrically connected to each other and plug-in charging is being carried out, or, when plug-in charging is scheduled to be carried out based on a programmed timer and the like, the plug-in ECU <NUM> charges the main battery <NUM> by supplying an external power supply (commercial power supply) from the charging station to the main battery <NUM>. Further, when the main battery <NUM> is being charged by the external power supply, the solar ECU <NUM> supplies the electric power generated from solar light to the main battery <NUM>.

At this stage, based on communication to/from the solar ECU <NUM>, when electric power is being supplied from the solar charger <NUM> to the main battery <NUM>, the plug-in ECU <NUM> selects the charging power supply line PUL4 as the supply path for the electric power (current) from the external power supply, and via the charging power supply line PUL4 and the charging power supply line PUL3 electrically connected to the solar charger <NUM>, supplies electric power (current) to the main battery <NUM>. In other words, when the electric power generated from solar light is being supplied from the solar charger <NUM>, the plug-in ECU <NUM> merges the electric power (current) being supplied from the external power supply with the electric power (current) being supplied via the charging power supply line PUL3, and supplies the merged electric power to the main battery <NUM>.

As a result, the electric power required in order to charge the main battery <NUM> can be met by the electric power supplied from the external power supply and the electric power generated from solar light. In other words, of the amount of electric power required to charge the main battery <NUM>, the amount of electric power supplied from the plug-in charger <NUM> is obtained by subtracting the amount of electric power supplied from the solar charger <NUM> from the amount of electric power required to charge the main battery <NUM>. Therefore, when the electric power from the solar charger <NUM> is used in conjunction with plug-in charging, the amount of electric power (current) supplied from the external power supply in order to charge the main battery <NUM> decreases. This enables the driver of the vehicle <NUM> to reduce the charging costs that arise through the use of the external power supply (commercial power supply).

On the other hand, regarding the electric power stored in the main battery <NUM>, the ratio of electric power supplied from the solar charger <NUM>, namely, the ratio of the electric power generated from solar light, which is renewable energy, can be actively increased. As a result, for example, depending on the region in which the vehicle <NUM> is traveling, fuel consumption (electricity consumption) is calculated based on the ratio of the electric power generated from solar light, and from an environmental protection perspective, the driver of the vehicle <NUM> may receive preferential treatment due to improved fuel consumption (electricity consumption).

Further, for example, when electric power is not being supplied from the solar charger <NUM> to the main battery <NUM> because the amount of electric power generated by the in-vehicle solar cell <NUM> is low due to bad weather, the plug-in ECU <NUM> supplies electric power (current) to the main battery <NUM> by selecting the charging power supply line PUL2 as the supply path for the electric power (current) from the external power supply. As a result, the main battery <NUM> can be reliably charged using the stably-supplied external power supply (commercial power supply), which allows the driver to use the vehicle <NUM> in accordance with his/her own schedule.

When the plug-in charger <NUM> of the vehicle <NUM> and the charging station have been electrically connected to each other and charging of the main battery <NUM> has been completed as described above, the plug-in ECU <NUM> stops plug-in charging. In other words, based on communication to/from the battery ECU <NUM>, when the SOC of the main battery <NUM> is at a preset SOC that is predetermined in order to determine the fully-charged state of the main battery <NUM>, the plug-in ECU <NUM> disconnects the electric power from the external power supply. On the other hand, based on the fact that plug-in charging by the plug-in ECU <NUM> has stopped, namely, that the supply of electric power from the external power supply has stopped, the solar ECU <NUM> changes the charging destination for supplying and storing the electric power generated from solar light from the main battery <NUM> to the sub-battery <NUM>.

As a result, dark current consumed by the various accessory devices can be suitably compensated for with the electric power supplied from the sub-battery <NUM> when the vehicle <NUM> is stopping or parking (in particular, when the engine <NUM> is stopped). Therefore, the sub-battery <NUM> can be prevented from becoming "dead" in advance. Further, by changing the charging destination to the sub-battery <NUM> when charging of the main battery <NUM> is complete, overcharging of the main battery <NUM> can be avoided, with the result that the main battery <NUM> can be suitably protected.

When the ignition (I/G) has been switched by the driver to the "accessory" position, it can be determined that the driver or an occupant wants to operate and use an accessory device without starting the engine <NUM>, namely, without consuming gasoline or diesel. Therefore, the charging controller <NUM> selects the sub-battery <NUM> as the charging destination and supplies the electric power generated from solar light in order to continuously operate the accessory device in accordance with the driver's or occupant's wishes.

Specifically, similar to the above-mentioned case in (b-<NUM>) or the above-mentioned case in (c-<NUM>), the solar ECU <NUM> uses the low-voltage charging DC/DC converter in the charging control circuit 23a of the solar charger <NUM> to transform and rectify the electric power generated from solar light into a predetermined voltage, and then supplies the electric power to the sub-battery <NUM> via the low-voltage power supply line PTL2. Note that, in this case too, the solar charger <NUM> (solar ECU <NUM>) supplies the electric power generated from solar light to the sub-battery <NUM> so that the sub-battery <NUM> is not overcharged, based on an SOC detected by a charging sensor (not shown) included in the sub-battery <NUM>.

Thus, for example, in a situation in which the an accessory device is being operated by only the electric power of the sub-battery <NUM> in accordance with the wishes of the driver or the occupant, namely, in a situation in which consumption of the electric power stored in the sub-battery <NUM> is increasing, the wishes of the driver or the occupant can be suitably reflected by using the electric power generated from solar light. Further, by supplying the electric power generated from solar light to the sub-battery <NUM>, the sub-battery <NUM> can be suitably prevented from becoming "dead". Note that, even in this case, because the electric power supplied to the sub-battery <NUM> has a low voltage, as described above, a low-voltage power supply can be handled in the same manner as for traditional vehicles other than EVs, HVs, and PHVs, and as a result, the system and charging control can be simplified.

As can be understood from the above description, according to this embodiment, when the vehicle <NUM> is traveling, namely, when there is a possibility that the electric power of at least the main battery <NUM> is being supplied to the motor generator <NUM>, the electric power generated by the in-vehicle solar cell <NUM> can be prevented from being supplied to the main battery <NUM> directly from the in-vehicle solar cell <NUM>, or via the low-voltage battery <NUM>. This eliminates the need to execute more complex controls without having an effect on how the main battery <NUM> is managed based on, for example, high-voltage system management, high-voltage battery control, opening/closing control of an electric power opening/closing device (a relay etc.), and power supply control, namely, by avoiding competition among the controls and the like. Therefore, an increase in development scale and in development costs can be suppressed, and the electric power generated from solar light can be appropriately used.

Further, the electric power generated by the in-vehicle solar cell <NUM> can be temporarily stored in the low-voltage battery <NUM>, and the generated electric power can be supplied to the sub-battery <NUM> when the vehicle <NUM> is traveling. In addition, by temporarily storing the electric power generated by the in-vehicle solar cell <NUM> in the low-voltage battery <NUM>, when the vehicle <NUM> is stopping of parking, obviously not only can the electric power be supplied to the sub-battery <NUM>, but the electric power generated from solar light can also be supplied to the main battery <NUM>. As a result, the electric power generated by the in-vehicle solar cell <NUM> can be used in an even more efficient manner.

In the above-mentioned embodiment, the electric power supply unit <NUM> of the vehicle <NUM> includes the low-voltage battery <NUM>, and the electric power generated from solar light generated by the in-vehicle solar cell <NUM> is temporarily (provisionally) stored in the low-voltage battery <NUM>. In this case, as illustrated in <FIG>, the low-voltage battery <NUM> may be omitted, and the electric power generated from solar light may be temporarily (provisionally) stored in the sub-battery <NUM>.

Specifically, in this case, as illustrated in <FIG>, the solar ECU <NUM> temporarily (provisionally) stores the electric power generated from solar light by the in-vehicle solar cell <NUM> in the sub-battery <NUM> via the charging control circuit 23a of the solar charger <NUM>. Note that, as described above with respect to the various different situations, the electric power generated from solar light to be stored in the sub-battery <NUM> may be used by supplying the electric power from the sub-battery <NUM>. In particular, in a situation in which the main battery <NUM> is selected as the charging destination, such as in the case of (b-<NUM>), the solar ECU <NUM> executes charging control when the level of electric power temporarily stored in the sub-battery <NUM> is at least a predetermined operational electric power level or more. Specifically, when the level of electric power stored in the sub-battery <NUM> is the predetermined operational electric power level or more, as illustrated in <FIG>, after verification by the verification ECU <NUM>, the solar ECU <NUM> outputs a startup signal and starts the battery ECU <NUM>, the hybrid ECU <NUM>, and the plug-in ECU <NUM>.

In particular, when the charging relay <NUM> is switched by the battery ECU <NUM> to a closed state (connected state), as illustrated in <FIG>, the solar ECU <NUM> raises (pumps up) and rectifies the low-voltage electric power temporarily stored in the sub-battery <NUM> with a high-voltage charging DC/DC converter in the charging control circuit 23a of the solar charger <NUM> to a predetermined voltage in a short period of time via the low-voltage power supply line PTL2, and supplies the electric power whose voltage has been converted into a high voltage to the main battery <NUM> via the charging power supply line PUL3 and the charging power supply line PUL2. As a result, the battery ECU <NUM> can, by controlling charging in a known manner, store the electric power (electric power generated from solar light) supplied from the sub-battery <NUM> by the solar charger <NUM> (solar ECU <NUM>) in the main battery <NUM>.

Therefore, according to this modified example, there is no need to separately include the low-voltage battery <NUM> for temporarily (provisionally) storing the electric power generated from solar light by the in-vehicle solar cell <NUM>. Consequently, an increase in costs resulting from including the low-voltage battery <NUM> can be suppressed and there is no need to secure a space for arranging the low-voltage battery <NUM>, which enables space savings to be made and a light weight to be achieved. The other advantageous effects that can be obtained by the modified example are the same as the advantageous effects obtained by the embodiment described above.

The implementation of the present invention is not limited to the above-mentioned embodiment and modified example, the scope of which is defined in the appended claims. Various changes may be made within the scope of the claims.

For example, in the above-mentioned embodiment, the electric power generated from solar light by the in-vehicle solar cell <NUM> is temporarily stored in the low-voltage battery <NUM>, and in the above-mentioned modified example, the electric power generated from solar light is temporarily stored in the shared sub-battery <NUM>. However, it is also possible for the electric power generated from solar light to be supplied to the main battery <NUM> and the sub-battery <NUM> without temporarily storing the electric power in the low-voltage battery <NUM>, or for the electric power generated from solar light to be supplied to the main battery <NUM> without temporarily storing the electric power in the sub-battery <NUM>.

In this case too, the electric power generated from solar light can be prevented from being supplied to the main battery <NUM> while the vehicle <NUM> is traveling. Further, when the vehicle <NUM> is not traveling, because the electric power generated from solar light can be directly supplied from the in-vehicle solar cell <NUM> to the main battery <NUM> via the solar charger <NUM>, the main battery <NUM> can be charged while ensuring reliability and safety during handling of the high-voltage power supply. Note that, in this case, the frequency with which the various electronic components and the various ECUs included in order to ensure reliability and safety are operated increases. Consequently, the charging efficiency (SOC) of the main battery <NUM> may deteriorate by an amount corresponding to the increase in the amount of electric power consumed by operating those electronic components compared with the above-mentioned embodiment and modified example.

Further, in the above-mentioned embodiment and modified example, for example, in the case of (c-<NUM>), the electric power supplied from the solar charger <NUM> to the main battery <NUM> (namely, electric power generated from solar light having an increased voltage), and the electric power from the external power supply (commercial power supply) supplied from the plug-in charger <NUM> to the main battery <NUM> are merged. As a result, the ratio of renewable energy to the electric power (electrical energy) stored in the main battery <NUM> increases, and the amount of electric power bought from the commercial power supply is reduced.

Claim 1:
A charging control device configured to use an in-vehicle solar cell (<NUM>) for installation in a vehicle (<NUM>);
the vehicle (<NUM>) comprising:
a motor generator (<NUM>, <NUM>) configured to generate a driving force and to generate regenerative electric power; and
a main battery (<NUM>) electrically connected to the motor generator (<NUM>, <NUM>), the main battery (<NUM>) being configured to supply electric power to the motor generator (<NUM>, <NUM>) and to store the regenerative electric power;
the vehicle (<NUM>) being capable of traveling using at least the driving force generated by the motor generator (<NUM>, <NUM>), characterized in that
the vehicle (<NUM>) comprises:
a sub-battery (<NUM>) configured to supply electric power to various accessory devices mounted on the vehicle (<NUM>), and in that
the charging control device comprises:
traveling determination means for determining whether or not the vehicle (<NUM>) is traveling,
an electric power supply unit (<NUM>) comprising the in-vehicle solar cell (<NUM>), which is configured to supply electric power generated by the in-vehicle solar cell (<NUM>) to the main battery (<NUM>) and the sub-battery (<NUM>); and
a charging control unit (<NUM>) configured to control charging of the main battery (<NUM>) and the sub-battery(<NUM>) using the electric power generated by the in-vehicle solar cell (<NUM>) and supplied from the electric power supply unit (<NUM>),
the charging control unit (<NUM>) being configured to:
when the traveling determination means determines that the vehicle (<NUM>) is traveling, prevent the electric power generated by the in-vehicle solar cell (<NUM>) from being supplied from the electric power supply unit (<NUM>) to the main battery (<NUM>) and supply the electric power generated by the in-vehicle solar cell (<NUM>) from the electric power supply unit (<NUM>) to the sub-battery (<NUM>).