Power source device and vehicle equipped with power source device

A power source device of present disclosure includes: a first power storage element; a second power storage element that is connected in parallel to the first power storage element and that has a lower internal resistance than an internal resistance of the first power storage element and a lower storage capacity than a storage capacity of the first power storage element; an opening and closing part that is connected between the first power storage element and the second power storage element and that switches between a disconnection state and a connection state; a charge circuit that is connected to an input route of the first power storage element and that performs a step-down operation; a discharge circuit that is connected to an output route of the second power storage element and that performs a step-up operation; and a controller that controls operations of the opening and closing part, the charge circuit, and the discharge circuit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application of the PCT International Application No. PCT/JP2017/033385 filed on Sep. 15, 2017, which claims the benefit of foreign priority of Japanese patent application No. 2016-182495 filed on Sep. 20, 2016, the contents all of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a power source device to be used for various vehicular electronic devices and to a vehicle equipped with the power source device.

BACKGROUND ART

Conventional power source device1will be described below with reference to the drawings.FIG. 5is a block diagram illustrating a configuration of conventional power source device1. Power source device1includes power storage element2, charge circuit3, discharge circuit4, and control circuit5. Charge circuit3is connected to an input route of power storage element2, and discharge circuit4is connected to an output route of power storage element2. Control circuit5controls operations of charge circuit3and discharge circuit4.

When charging power storage element2with electric power from an outside of power source device1, control circuit5activates charge circuit3and inactivates discharge circuit4. When discharging the electric power stored in power storage element2, control circuit5inactivates charge circuit3and activates discharge circuit4.

For example, PTL 1 is known as information on prior art documents related to the present disclosure.

CITATION LIST

Patent Literature

SUMMARY OF THE INVENTION

According to one aspect of the present disclosure, a power source device includes: a first power storage element; a second power storage element that is connected in parallel to the first power storage element, the second power storage element having a lower internal resistance than an internal resistance of the first power storage element and a lower storage capacity than a storage capacity of the first power storage element; an opening and closing part that is connected between the first power storage element and the second power storage element, the opening and closing part switching between a disconnection state and a connection state; a charge circuit that is connected to an input route of the first power storage element, the charge circuit performing a step-down operation; a discharge circuit that is connected to an output route of the second power storage element, the discharge circuit performing a step-up operation; and a controller that controls operations of the opening and closing part, the charge circuit, and the discharge circuit. When the opening and closing part is in the disconnection state, the first power storage element is disconnected from the second power storage element, the charge circuit performs the step-down operation to charge the first power storage element, and the discharge circuit stops operating. The discharge circuit stops operating over a predetermined time after the opening and closing part has switched from the disconnection state to the connection state. After the predetermined time has passed since switching of the opening and closing part from the disconnection state to the connection state, the discharge circuit starts the step-up operation to discharge electric power stored in the second power storage element and the first power storage element.

According to one aspect of the present disclosure, a vehicle includes: a vehicle body; a vehicle battery disposed in the vehicle body; a door disposed in the vehicle body; an operation member disposed in the door; a power source device that includes a first power storage element, a second power storage element that is connected in parallel to the first power storage element and that has a lower internal resistance than an internal resistance of the first power storage element and a lower storage capacity than a storage capacity of the first power storage element, an opening and closing part that is connected between the first power storage element and the second power storage element and that switches between a disconnection state and a connection state, a charge circuit that is connected to an input route of the first power storage element and that performs a step-down operation, a discharge circuit that is connected to an output route of the second power storage element and that performs a step-up operation, and a controller that controls operations of the opening and closing part, the charge circuit, and the discharge circuit, the power source device being disposed in the vehicle body; an engine switch connected between the vehicle battery and an input end of the charge circuit; a power route that connects the vehicle battery to an output terminal of the discharge circuit; and a vehicle load that is connected to the output terminal and that is disposed in the vehicle body. In response to an operation of the operation member, the controller switches the opening and closing part from the disconnection state to the connection state. After a predetermined time has passed since switching of the opening and closing part from the disconnection state to the connection state, the discharge circuit starts the step-up operation to supply the vehicle load with electric power stored in the second power storage element and the first power storage element.

According to another aspect of the present disclosure, in the vehicle, the controller or the charge circuit further determines whether the vehicle body is in a normal state or in an abnormal state. When vehicle body is determined to be in the abnormal state and the operation member is operated, the controller sets the opening and closing part to the connection state, and the discharge circuit performs the step-up operation to discharge the electric power stored in the second power storage element and the first power storage element. The electric power is supplied from the discharge circuit to the vehicle load.

DESCRIPTION OF EMBODIMENTS

First Exemplary Embodiment

When a capacitor having a low internal resistance is used as power storage element2in power source device1illustrated inFIG. 5, for example, power source device1can output a large current in a short time even if a capacitance of power storage element2is small. However, power source device1may have difficulty in continuously supplying electric power over a long period.

If a lead storage battery having a high internal resistance is used as power storage element2, for example, power source device1can output electric power over a long time. However, power storage element2needs to have a very large capacitance to output a large current in a short time.

As described above, power source device1illustrated inFIG. 5may have difficulty in supplying a large current over a long period when its capacitance is small.

Herein, power source device6of the present disclosure will be described with reference toFIGS. 1 and 3.

[Configuration of Power Source Device6]

FIG. 1is a block diagram illustrating a configuration of a power source device according to a first exemplary embodiment of the present disclosure. Power source device6includes: first power storage element7; second power storage element8connected in parallel to first power storage element7; opening and closing part9connected between first power storage element7and second power storage element8; charge circuit10; discharge circuit11; and controller12that controls operations of opening and closing part9, charge circuit10, and discharge circuit11.

Second power storage element8has a lower internal resistance than an internal resistance of first power storage element7. Furthermore, second power storage element8has a lower storage capacity than a storage capacity of first power storage element7. Opening and closing part9performs a switching operation to connect first power storage element7and second power storage element8to each other or to disconnect first power storage element7and second power storage element8from each other. Charge circuit10, which is connected to an input route of first power storage element7, performs a step-down operation. Discharge circuit11, which is connected to an output route of second power storage element8, performs a step-up operation.

When controller12controls opening and closing part9so as to be in a disconnection state, charge circuit10performs the step-down operation to charge first power storage element7. At this time, discharge circuit11is inactivated.

When controller12controls opening and closing part9so as to be in a connection state, charge circuit10is inactivated. In this case, when opening and closing part9switches from the disconnection state to the connection state, second power storage element8is charged with the electric power stored in first power storage element7over a predetermined time. At this time, discharge circuit11is inactivated. Then, after the predetermined time has passed since switching of opening and closing part9from the disconnection state to the connection state, discharge circuit11starts performing the step-up operation. While controller12controls opening and closing part9so as to be in the connection state, discharge circuit11continues to perform the step-up operation. As a result, the electric power stored in both second power storage element8and first power storage element7is discharged through discharge circuit11.

According to the above configuration and operation, when power source device6needs to supply electric power, second power storage element8that has a low internal resistance and thus can discharge a large current in a short time is first charged by first power storage element7for a predetermined time, and then discharges the current. When a voltage of second power storage element8starts decreasing as a result of the discharging, first power storage element7that can discharge a current over a long period replaces second power storage element8and starts discharging the electric power. In this way, power source device6can output a required amount of electric power over a necessary period.

In other words, in a state where power source device6needs to output electric power, controller12controls opening and closing part9, charge circuit10, and discharge circuit11so as to sequentially perform the following operations: second power storage element8is charged with electric power; second power storage element8discharges the electric power; and first power storage element7discharges the electric power.

According to power source device6of the present disclosure, power source device6outputs electric power stored in second power storage element8during an initial discharge period in which a power supply target has a large load. When the load of the power supply target becomes lower after a predetermined time has passed since the start of the discharging, power source device6can continuously output the electric power stored in first power storage element7over a long period. As a result, power source device6can output a required amount of electric power to the power supply target in accordance with situations and can continuously output the electric power.

[Vehicle Equipped with Power Source Device6]

Next, a description will be given regarding an example case where power source device6described above is installed in vehicle13A.

FIG. 2is a block diagram illustrating a configuration of a vehicle equipped with the power source device according to the first exemplary embodiment of the present disclosure;FIG. 3is a timing chart of an operation performed by the power source device according to the first exemplary embodiment of present disclosure.FIG. 4is a timing chart of an operation performed by the vehicle according to the first exemplary embodiment of the present disclosure. The timing chart inFIG. 3overlaps with the timing chart inFIG. 4; therefore, only the timing chart inFIG. 4will be described below and the timing chart inFIG. 3will not be described.

Power source device6described above is installed in vehicle body13. Input terminal14of power source device6is connected, via engine switch16, to vehicle battery15mounted in vehicle body13. Output terminal17of power source device6is connected to vehicle load18. Control terminal19of power source device6is connected to controller12and receives signals from an outside of power source device6and from an inside of vehicle13A. In a typical case, vehicle battery15is connected to vehicle load18via power route20. Disposed on power route20is backflow preventing diode21, which blocks a current from flowing from output terminal17to vehicle battery15.

In this exemplary embodiment, a description will be given regarding an example in which vehicle load18is a door latch motor disposed in door22that is provided in vehicle body13and an operation member for use in outputting an instruction to vehicle load18(door latch motor) is door handle23.

Vehicle load18(door latch motor) needs to enable a passenger to get in or out of vehicle13A, regardless of whether vehicle13A starts up. Thus, vehicle load18is connected to vehicle battery15via power route20. In other words, vehicle load18is in a state of being able to receive electric power from vehicle battery15.

When the passenger inside or outside vehicle13A attempts to open door22by using door handle23, which is the operation member, disposed in door22of vehicle body13, vehicle battery15supplies electric power to vehicle load18. As a result, vehicle load18(door latch motor) is driven, thereby enabling the passenger to open door22. Simultaneously with the supply of the electric power from vehicle battery15to vehicle load18through power route20, vehicle battery15may also supply the electric power to power source device6, and in turn, power source device6may supply the electric power to vehicle load18.

Next, a description will be given of an operation performed by vehicle13A equipped with power source device6, with reference toFIGS. 2 and 3. When the passenger inside or outside vehicle13A attempts to open door22of vehicle body13by operating door handle23disposed in door22, control terminal19receives operation instruction signal S1generated in response to an instruction of opening door handle23. A timing when control terminal19receives operation instruction signal S1corresponds to time T1in the timing chart ofFIG. 3. The timing chart of opening and closing part9inFIG. 3indicates whether opening and closing part9is in a connection state or in a disconnection state. The state of opening and closing part9is switched in response to a passenger's operation of door handle23. More specifically, in a period before time T1, opening and closing part9is in the disconnection state, in other words, in a state where door handle23is not operated. When the passenger starts operating door handle23(time T1), opening and closing part9switches to the connection state. The connection state of opening and closing part9is maintained until the passenger finishes operating door handle23(time T4).

If vehicle13A has already started up before time T1, the passenger has not operated door handle23, and engine switch16is in a connection state. When vehicle13A has started up as in this state, vehicle battery15supplies the electric power to charge circuit10through both engine switch16and input terminal14. Then, charge circuit10is activated to charge first power storage element7.

Engine switch16may be either a switch for use in starting up vehicle13A or a switch that operates in relation to the start-up of vehicle13A.

If vehicle body13has not started up before time T1, first power storage element7is already charged during a charging operation performed when vehicle13A starts up the last time. As a result, first power storage element7is almost constantly maintained in a fully charged state.

First power storage element7is preferably an element, such as a capacitor or a lithium battery, that is resistant to deterioration even in a constantly, fully charged state.

Regardless of whether vehicle13A starts up, controller12inactivates charge circuit10at time T1(or maintains charge circuit10in an inactive state). As described above, at time T1, controller12switches opening and closing part9from the disconnection state to the connection state. While opening and closing part9is in the connection state, both first power storage element7and second power storage element8are connected in parallel to discharge circuit11.

Second power storage element8may be an electric double layer capacitor whose internal resistance and storage capacity are lower than the internal resistance and storage capacity, respectively, of first power storage element7. If second power storage element8is an electric double layer capacitor, second power storage element8is typically maintained in an uncharged state or in a state of being charged at a voltage value lower than a threshold, in order to avoid deterioration of second power storage element8. For this purpose, before time T1, second power storage element8is set to a state of being charged at voltage VL, which is lower than or equal to the threshold. When opening and closing part9enters the connection state at time T1, first power storage element7is connected in parallel to second power storage element8. As a result, second power storage element8is charged until second power storage element8and first power storage element7have the same potential, so that the voltage of second power storage element8increases.

Immediately after time T1, first power storage element7enters a state of supplying the electric power to second power storage element8. Therefore, the voltage of first power storage element7decreases temporarily in a very short period. Then, the voltage of first power storage element7returns to voltage VII, which is substantially equal to the initial charged voltage. A reason why first power storage element7can supply the electric power to second power storage element8immediately after time T1is that the storage capacity of first power storage element7is set to be higher than the storage capacity of second power storage element8. After that, the voltage variation is very slightly continued.

At time T2, which is a time point when a predetermined time has passed since time T1, discharge circuit11is activated. Since second power storage element8has already been charged by first power storage element7at time T2, the voltage of second power storage element8has a value equal to or close to charged voltage VH, which is the initially charged voltage of first power storage element7. In this case, discharge circuit11is activated at time T2, which is the time point when the predetermined time has passed after time T1.

In order for discharge circuit11to operate precisely, controller12, charge circuit10, or discharge circuit11may detect a voltage of second power storage element8and, at time T2, which is a time point when the detected voltage reaches or exceeds a predetermined value, controller12may activate discharge circuit11.

When discharge circuit11is activated at time T2, first power storage element7and second power storage element8that have been interconnected in parallel are at substantially the same potential. In this case, both of first power storage element7and second power storage element8would supply the electric power to discharge circuit11. However, as described above, the internal resistance of second power storage element8is smaller than the internal resistance of first power storage element7, and a wire between second power storage element8and discharge circuit11is shorter than a wire between first power storage element7and discharge circuit11. Assuming that both wires have the same width, a conductor resistance present between discharge circuit11and second power storage element8is lower than a conductor resistance present between discharge circuit11and first power storage element7. Therefore, immediately after discharge circuit11is activated, discharge circuit11acquires the electric power stored in second power storage element8in a short time, in preference to the electric power stored in first power storage element7, and then increases a voltage. As a result, discharge circuit11supplies a large current, namely, high electric power to vehicle load18through output terminal17in a short time between times T2and T3.

Since discharge circuit11acquires the electric power stored in second power storage element8in the short time in preference to the electric power stored in first power storage element7, the voltage of second power storage element8temporarily decreases over a period between times T2and T3. However, immediately after time T3, the voltage of second power storage element8increases to voltage VII, which is the initially charged voltage of first power storage element7or to a value close to voltage VII, because first power storage element7is connected in parallel to second power storage element8via opening and closing part9.

When the electric power stored in second power storage element8decreases to a very low value at time T3, discharge circuit11in turn acquires the electric power stored in first power storage element7and then steps up a voltage. As a result, discharge circuit11supplies the electric power stored in first power storage element7to vehicle load18via output terminal17over a period between times T3and T4. Discharge circuit11may have difficulty in outputting the electric power stored in first power storage element7in a form of an instantly large current, but can output a constant current over a long time. This enables discharge circuit11to continuously supply the electric power to vehicle load18through output terminal17. It should be noted that, over the period between times T3and T4, the charging of second power storage element8with electric power from first power storage element7and supplying the electric power from first power storage element7to discharge circuit11is performed simultaneously.

At time T4, which is a time point when the passenger finishes operating door handle23, controller12switches opening and closing part9from the connection state to the disconnection state. Simultaneously, controller12inactivates discharge circuit11. In response, discharge circuit11stops discharging the electric power to vehicle load18through output terminal17. As described above, first power storage element7is constantly maintained in the almost fully charged state. Thus, even after time T4, first power storage element7is maintained in the almost fully charged state.

After time T4, second power storage element8discharges the electric power for the sake of an extended lifetime, so that the voltage of second power storage element8returns to voltage VL, which is the initial voltage. A state where second power storage element8discharges the electric power is depicted after time T4by a solid line inFIG. 4. A state where second power storage element8does not discharge the electric power is depicted by a broken line. For example, a discharger (not illustrated) may be used to decrease the charged voltage of second power storage element8to voltage VL or lower.

As is clear from the state of the discharged electric power illustrated inFIG. 4, discharge circuit11in vehicle13A can supply high electric power to vehicle load18immediately after starting the power supply, and then can continuously supply vehicle load18with electric power lower than the initial electric power. Vehicle load18needs high electric power in an initial operation, especially if vehicle load18is a motor. However, when continuing to operate, the motor does not need as high electric power as the initial electric power. Therefore, vehicle13A equipped with power source device6according to the present disclosure enables the passenger to perform an open operation of door handle23over a long time.

Vehicle13A of the present disclosure can supply electric power from both of discharge circuit11and power route20to vehicle load18. Even if vehicle battery15deteriorates with its voltage decreasing, vehicle13A can drive vehicle load18until the electric power stored in first power storage element7runs out.

Even if first power storage element7and second power storage element8deteriorate, vehicle battery15can drive vehicle load18through power route20.

As described above, vehicle13A is equipped with power source device6that can constantly supply the electric power to vehicle load18.

Second Exemplary Embodiment

Next, with reference toFIGS. 2 and 4, a description will be given of vehicle13A in which power source device6can supply electric power to vehicle load18in an emergency, such as in a case where vehicle body13or vehicle13A is damaged by, for example, an accident.

It should be noted that, although the block diagram inFIG. 2is also applicable to second exemplary embodiment, the second exemplary embodiment differs from first exemplary embodiment only in function of controller12or charge circuit10.

Controller12determines whether vehicle body13and vehicle13A are in a normal state or an abnormal state. To perform a method of determining whether vehicle body13and vehicle13A are in a normal state or an abnormal state, in the second exemplary embodiment, controller12or charge circuit10detects a voltage at input terminal14and makes the determination during the start-up of vehicle13A.

When vehicle13A starts up, vehicle battery15supplies electric power to input terminal14of power source device6through engine switch16being in a connection state. If vehicle13A is involved in an accident, for example, and vehicle body13or vehicle battery15is thereby damaged, the voltage at input terminal14may decrease. Thus, when engine switch16is in the connection state, if the voltage at input terminal14decreases to less than a predetermined value, controller12or charge circuit10may determine that vehicle13A and vehicle body13are in an emergency state due to an accident. The determination as to an accident of vehicle13A and vehicle body13may be made in consideration of detection using a crash sensor (not illustrated) provided in vehicle body13.

Needless to say, when engine switch16is in the connection state, if the voltage at input terminal14is kept at a voltage higher than the predetermined value, controller12or charge circuit10may determine that vehicle13A and vehicle body13are in a normal state.

First, a description will be given regarding a case where vehicle13A and vehicle body13are determined to be in the normal state. In this state, vehicle battery15can supply the electric power to vehicle load18through power route20. Accordingly, opening and closing part9in power source device6is constantly in the disconnection state, regardless of whether control terminal19receives (or does not receive) operation instruction signal S1generated in response to an instruction of opening door handle23.

The state where vehicle13A and vehicle body13are determined to be in the normal state corresponds to a period before time T1in the timing chart ofFIG. 4. Then, over a period between times T and T0, which corresponds to a period in which door handle23is operated, vehicle battery15drives vehicle load18through power route20.

In the state where vehicle13A and vehicle body13are determined to be in the normal state, charge circuit10in power source device6charges first power storage element7with the electric power from vehicle battery15, in order to prepare for an abnormal state where vehicle battery15loses the electric power.

A period in which charge circuit10charges first power storage element7, which corresponds to the period between times T0and T1indicated by the word “activation” inFIG. 4is depicted as continuous, constant charging inFIG. 4. However, this period may be intermittent charging in which charging periods and break periods are alternately set at predetermined intervals.

Even if vehicle13A and vehicle body13are determined to be in the normal state, charge circuit10stops charging over a period in which the passenger or another person operates door handle23(over the period between times T and T0). This is to reduce an increase in a burden on vehicle battery15, which may be caused by the supply of the electric power from vehicle battery15to both charge circuit10and vehicle load18.

A description will be given regarding a case where vehicle13A and vehicle body13are determined to be in the abnormal state. In this state, vehicle battery15cannot supply the electric power to vehicle load18or the power source device. As described above, when engine switch16is in the connection state, if the voltage at input terminal14decreases to less than the predetermined value, controller12or charge circuit10determines that vehicle13A and vehicle body13are in the emergency state due to an accident. In the timing chart ofFIG. 4, at time T1, controller12determines that vehicle13A and vehicle body13are in the abnormal state. A period after time T1corresponds to a period in which the abnormal state is continued.

When vehicle13A and vehicle body13are determined to be in the abnormal state, charge circuit10stops charging first power storage element7which has been performed in a continuous or intermittent manner. Then, at the same time when or immediately after charge circuit10stops charging, opening and closing part9switches from the disconnection state to the connection state. The operations performed by charge circuit10and opening and closing part9are controlled by controller12. During the period after time T1, controller12continues to operate in order to maintain a state of being able to receive operation instruction signal S1through control terminal19. In this case, controller12may cause first power storage element7to act as a power source. Since controller12consumes only a small amount of electric power, the amount of electric power stored in first power storage element7does not greatly decrease.

In general, when vehicle13A and vehicle body13are involved in an accident at time T1, the period between times T1and T2, in which the passenger or a rescuer operates door handle23, becomes longer than usual. By being connected to first power storage element7, second power storage element8that has been insufficiently charged until time T1is charged. In this case, in order to reserve a time for charging second power storage element8, a predetermined period may be set within the period between times T1and T2as a period for prohibiting an operation of door handle23. However, the period for prohibiting an operation of door handle23does not necessarily have to be set, because first power storage element7, in fact, can charge second power storage element8in only about 10 seconds.

Immediately after time T1, first power storage element7enters a state of supplying the electric power to second power storage element8. Therefore, the voltage of first power storage element7temporarily decreases in a very short period and then returns to voltage VII, which is substantially equal to an initial charged voltage. This is because a storage capacity of first power storage element7is set to be higher than a storage capacity of second power storage element8. After that, the voltage continues to slightly vary. This behavior is similar to the behavior in the first exemplary embodiment described above.

In response to the passenger or rescuer's operation of door handle23at time T2, operation instruction signal S1is transmitted to control terminal19. In response, discharge circuit11discharges the electric power from both second power storage element8and first power storage element7. Vehicle load18is driven by means of the electric power supplied from discharge circuit11through output terminal17. When vehicle13A and vehicle body13are determined to be in the abnormal state, opening and closing part9that has switched from the disconnection state to the connection state at time T1maintains the connection state in which power source device6can supply the electric power to vehicle load18, until time T4at which the passenger or the rescuer finishes operating door handle23.

In the second exemplary embodiment, over the period between times T3and T4, first power storage element7charges second power storage element8. Simultaneously and in parallel with this, first power storage element7supplies the electric power to discharge circuit11. This operation is similar to the operation in the first exemplary embodiment.

In the second exemplary embodiment, after time T4, discharge circuit11no longer has to discharge the electric power stored in second power storage element8and thus may simply maintain the electric power in second power storage element8(this state is depicted by a broken line inFIG. 4). This is because power source device6needs to operate under a special condition, more specifically, in an emergency situation where vehicle body13is involved in an accident. In this way, power loss of second power storage element8is reduced, which enables power source device6to operate in a much longer period after time T4.

Power source device6can repeat the operation that has been performed over the period between times T1and T4multiple times, especially when vehicle13A is involved in an accident. This is because first power storage element7is a capacitor or lithium battery that is resistant to deterioration even in a constantly, fully charged state. If a capacitor or lithium battery that is resistant to deterioration is used, power source device6can continuously or repeatedly discharge the electric power. Thus, over the period between times T1and T2, which is within the period between times T1and T4that repeatedly appears, first power storage element7may repeat charging second power storage element8.

When controller12determines that vehicle13A (vehicle body13) is in the abnormal state due to an accident and thereby repeats the above operation that has been performed in the period between times T1and T4, charge circuit10does not have to operate in a period between time T4and next time T1even if opening and closing part9is in the disconnection state. A reason is that, when controller12is determined to be in the abnormal state, vehicle battery15that is to supply the electric power to charge circuit10can no longer supply the electric power. Thus, the operation performed by charge circuit10is unnecessary. In order to avoid wasting the electric power in an unnecessary operation, controller12inactivates charge circuit10even if opening and closing part9is in the disconnection state.

As a result of the above, the passenger of vehicle13A can repeatedly attempt to escape from vehicle13A multiple times after an accident occurs. Likewise, the rescuer of vehicle13A can repeatedly attempt to rescue the passenger in vehicle body13multiple times. When first power storage element7is a capacitor or lithium battery that is resistant to deterioration even in a constantly, fully charged state, first power storage element7does not spontaneously discharge the electric power for about 100 hours. Therefore, even if the passenger cannot escape from vehicle13A on his/her own and the rescuer needs time to reach vehicle13A, power source device6can maintain the electric power, especially stored in first power storage element7until the passenger is rescued and thereby can operate at necessary opportunities.

As indicated by a curve of discharged power in the timing chart ofFIG. 4, discharge circuit11can initially supply high electric power to vehicle load18and then can continuously supply electric power lower than the initial electric power to vehicle load18. Therefore, in an emergency case where vehicle13A is involved in an accident, discharge circuit11can simultaneously activate a plurality of vehicle loads18that require large currents for activation. For example, when the passenger or the rescuer operates door handle23during the process described above, only if vehicle13A is determined to be involved in an accident, discharge circuit11may drive door latch motors (vehicle loads18) so as to open all doors22, in response to an operation of one of door handles23in respective doors22provided in vehicle body13.

Only if vehicle13A is determined to be involved in an accident, when discharge circuit11first outputs the electric power, power source device6may simultaneously drive the door latch motors as vehicle loads18and door lock release motors by means of the electric power.

In the exemplary embodiments described herein, a case where vehicle load18is a door latch motor has been used by way of example. Power source device6of present disclosure effectively serves as an emergency power source for vehicle load18when vehicle13A is determined to be involved in an accident, because vehicle load18, which may be a motor, requires a large current to produce high torque upon startup but, when continuing to operate, can maintain its operation by receiving a constant current.

The above example has described a procedure of the operation performed by power source device6when vehicle13A is determined to be involved in an accident, in response to an occurrence of an event where engine switch16is in the connection state but the voltage at input terminal14is lower than the predetermined value, or in response to a detection of the crash sensor.

One example of other abnormal states is a case where submersion of vehicle body13is detected. In this case, power source device6may perform the operation starting from time T1without receiving a passenger's operation, thereby forcedly opening power windows provided in doors22as vehicle loads18. Alternatively, power source device6may open the power window in response to a passenger's operation of a window opening and closing instruction unit as an operation unit. If a motor for the power window is used in each door22as vehicle load18, in general, the motor requires a large current upon startup but, when continuing to operate, can maintain its operation by receiving a constant current. Therefore, discharge circuit11can supply high electric power to vehicle load18in an initial state of start of discharge and then can continuously supply electric power lower than the initial electric power. In this way, power source device6of the present disclosure can reliably drive the power windows, namely, vehicle loads18.

Power source device6of the present disclosure can supply the electric power to an outside of power source device6in an emergency case where the electric power of a main battery (vehicle battery15) is lost. When power source device6needs to supply electric power to the outside, second power storage element8that has a low internal resistance and thus can discharge a large current in a short time is first charged, and then the electric power is discharged to the outside. After second power storage element8discharges the electric power, first power storage element7that can discharge the electric power over a long period, in turn, starts discharging the electric power. In this way, power source device6can supply a required amount of electric power over a necessary period. Consequently, power source device6of present disclosure can drive various loads.

Power source device6of the above exemplary embodiments is provided with, as an independent internal component in power source device6, controller12that controls opening and closing part9, charge circuit10, and discharge circuit11. However, controller12does not necessarily have to be formed as a single circuit block. Alternatively, functions of controller12may be fulfilled by power source device6or may be separately provided in other components.

Controller12may be provided as a part of a vehicle controller (not illustrated) that controls entire vehicle13A. In this case, both controller12and control terminal19in the block diagrams only have to fulfill a function of a transceiver circuit that transmits or receives signals between the above vehicle controller and power source device6.

SUMMARY

The power source device6of the present disclosure includes: first power storage element7; second power storage element8that is connected in parallel to first power storage element7and that has a lower internal resistance than an internal resistance of first power storage element7and a lower storage capacity than a storage capacity of first power storage element7; an opening and closing part9that is connected between first power storage element7and second power storage element8and that switches between a disconnection state and a connection state; charge circuit10that is connected to an input route of first power storage element7and that performs a step-down operation; discharge circuit11that is connected to an output route of second power storage element8and that performs a step-up operation; and controller12that controls operations of opening and closing part9, charge circuit10, and discharge circuit11. When opening and closing part9is in the disconnection state, first power storage element7is disconnected from second power storage element8, charge circuit10performs the step-down operation to charge first power storage element7, and discharge circuit11stops operating. Discharge circuit11stops operating over a predetermined time after opening and closing part9has switched from the disconnection state to the connection state. After the predetermined time has passed since switching of opening and closing part9from the disconnection state to the connection state, discharge circuit11starts the step-up operation to discharge electric power stored in second power storage element8and first power storage element7.

In power source device6of the present disclosure, first power storage element7preferably charges second power storage element8over the predetermined time after opening and closing part9has switched from the disconnection state to the connection state.

In power source device6of the present disclosure, charge circuit10preferably stops operating when opening and closing part9is in the connection state.

In power source device6of the present disclosure, a conductor resistance between discharge circuit11and second power storage element8is preferably set to be lower than a conductor resistance between discharge circuit11and first power storage element7.

Vehicle13A equipped with power source device6, described above, of the present disclosure includes: vehicle body13; vehicle battery15disposed in vehicle body13; door22disposed in vehicle body13; door handle23(operation member) disposed in a door, power source device6; engine switch16connected between vehicle battery15and input terminal14of charge circuit10; power route20that connects vehicle battery15to output terminal17of discharge circuit11; and vehicle load18that is disposed in vehicle body13and that is connected to output terminal17. In response to an operation of door handle23, controller12preferably switches opening and closing part9from the disconnection state to the connection state. After a predetermined time has passed since switching of opening and closing part9from the disconnection state to the connection state, discharge circuit11starts the step-up operation to supply vehicle load18with electric power stored in second power storage element8and first power storage element7.

In vehicle13A of the present disclosure, controller12or charge circuit10preferably can determine whether vehicle body13is in a normal state or in abnormal state. When vehicle body13is determined to be in the abnormal state and door handle23is operated, controller12sets opening and closing part9to the connection state, and discharge circuit11performs the step-up operation to discharge the electric power stored in second power storage element8and first power storage element7. The electric power is thereby supplied from discharge circuit11to vehicle load18.

INDUSTRIAL APPLICABILITY

The power source device of the present disclosure can supply a required amount of electric power over a necessary period, thereby successfully driving various loads. Therefore, the power source device of the present disclosure is effectively applicable to various vehicular electronic devices.

REFERENCE MARKS IN THE DRAWINGS