In-vehicle power supply device

Abstract

To determine deterioration of a power storage unit without consuming dark current.SOLUTION: An on-vehicle power supply device 1 reduces the voltage of a power storage unit 2 in a discharge mode when receiving a vehicle start-up signal S1 and increases the voltage of the storage unit 2 in a charge mode. At least any one of the charge mode and the discharge mode is provided with a stop period TS for stopping a discharge operation or a charge operation. The on-vehicle power supply device detects the potential difference VP between a stop period voltage VS of the power storage unit 2 in the stop period TS and the operating voltage VD of the power storage unit 2 immediately before or immediately after the stop period TS, when the stop period TS is provided in the discharge mode, obtains a first resistance value R1 from a first current and the potential difference VP between the operating voltage VD and the stop period voltage VS, when the stop period TS is provided in the charge mode, obtains a second resistance value R2 from the first current and the potential difference VP, and when the first resistance value R1 or the second resistance value R2 is equal to or more than a threshold resistance value RTH, sends a warning signal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an in-vehicle power supply device used in various vehicles.

Background Art

[0002] The conventional in-vehicle power supply device will be described below. The conventional in-vehicle power supply device has a function capable of detecting the deterioration state of a power storage unit included in the in-vehicle power supply device. Further, a function of transmitting a warning signal when the deterioration state is detected is provided.

[0003] Note that, as prior art document information related to the invention of this application, for example, Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional in-vehicle power supply device, the determination of deterioration of the power storage unit is performed at a timing when power is not required, such as after the vehicle is started and stopped. In this case, power for deterioration detection needs to be supplied to the in-vehicle power supply device during the start and stop of the vehicle.

[0006] As a result, there is a problem that the vehicle battery may be deteriorated by the standby current for operating the in-vehicle power supply device.

[0007] Therefore, an object of the present invention is to enable determination of deterioration of a power storage unit without consuming standby current.

Means for Solving the Problems

[0008] To achieve this objective, the present invention comprises a power storage unit, a charge / discharge circuit capable of charging and discharging the power storage unit and discharging power from the power storage unit in an emergency, and a control unit capable of detecting the voltage of the power storage unit and the current flowing through the charge / discharge circuit, receiving a vehicle start signal, and transmitting a warning signal, wherein when the vehicle start signal is received, the control unit operates the charge / discharge circuit with a first current in discharge mode to reduce the voltage of the power storage unit from a first voltage to a second voltage, and further operates the charge / discharge circuit with a second current in charge mode to increase the voltage of the power storage unit from the second voltage to a third voltage. The charging mode and the discharging mode are provided with a stop period during which the discharge operation or the charging operation is stopped. The control unit detects the potential difference between the voltage of the energy storage unit during the stop period and the operating voltage of the energy storage unit immediately before or after the stop period. If the stop period is provided in the discharge mode, it obtains a first resistance value using the potential difference and the first current. If the stop period is provided in the charging mode, it obtains a second resistance value using the potential difference and the first current. The control unit then issues the warning signal if the first resistance value or the second resistance value is greater than or equal to a threshold resistance value. [Effects of the Invention]

[0009] According to the present invention, degradation of the energy storage unit of the on-board power supply can be determined while the vehicle is running, and since power equivalent to dark current is not required, degradation of the energy storage unit can be determined without putting a burden on the vehicle battery and without causing any problems when discharging power in an emergency. [Brief explanation of the drawing]

[0010] [Figure 1] Circuit block diagram showing the configuration of the on-board power supply unit in an embodiment of the present invention. [Figure 2] First operating curve diagram showing the operation of the on-board power supply device in an embodiment of the present invention. [Figure 3]Second operating curve diagram showing the operation of the on-board power supply device in an embodiment of the present invention. [Figure 4] Circuit block diagram showing the configuration of a vehicle equipped with an on-board power supply unit according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings.

[0012] (Embodiment) Figure 1 is a circuit block diagram showing the configuration of the in-vehicle power supply unit 1 in an embodiment of the present invention, Figure 2 is a first operation curve diagram showing the operation of the in-vehicle power supply unit 1 in an embodiment of the present invention, and Figure 3 is a second operation curve diagram showing the operation of the in-vehicle power supply unit 1 in an embodiment of the present invention.

[0013] The on-board power supply unit 1 includes a power storage unit 2, a charge / discharge circuit 3, and a control unit 4. The charge / discharge circuit 3 is capable of charging the power storage unit 2 and discharging the power stored in the power storage unit 2, and is particularly capable of discharging the power stored in the power storage unit 2 in emergencies. The control unit 4 is capable of detecting the voltage stored in the power storage unit 2, detecting the current flowing through the charge / discharge circuit 3, receiving the vehicle start signal S1, and transmitting the warning signal S2.

[0014] The control unit 4 can cause the charge / discharge circuit 3 to perform operation in discharge mode and operation in charge mode. When the control unit 4 receives the vehicle start signal S1, it discharges the charge / discharge circuit 3 with a first current I1 in discharge mode, lowering the voltage of the energy storage unit 2 from the first voltage V1 to the second voltage V2. Furthermore, the control unit 4 charges the charge / discharge circuit 3 with a second current I2 in charge mode, raising the voltage of the energy storage unit 2 from the second voltage V2 to the third voltage V3.

[0015] Here, the control unit 4 operates the charge / discharge circuit 3 so that in at least one of the charge mode or discharge mode, there is a stop period TS during which the discharge operation in the discharge mode or the charge operation in the charge mode is stopped. The control unit 4 then detects the potential difference VP between the stop period voltage VS of the energy storage unit 2 during the stop period TS and the operating voltage of the energy storage unit 2 immediately before or after the stop period TS when the first current I1 or second current I2 is flowing.

[0016] If the stop period TS is set in discharge mode, the control unit 4 determines the first resistance value R1 using the potential difference VP and the first current I1. If the stop period TS is set in charge mode, the control unit 4 determines the second resistance value R2 using the potential difference VP and the second current I2. Then, if the first resistance value R1 or the second resistance value R2 is greater than or equal to the threshold resistance value RTH, the control unit 4 sends a warning signal S2.

[0017] With the above configuration and operation, the on-board power supply unit 1 can perform degradation checks on the energy storage unit 2 when it receives the vehicle start signal S1, in other words, when the vehicle equipped with the on-board power supply unit 1 is started, and the on-board power supply unit 1 is operational. For this reason, the on-board power supply unit 1 does not require power equivalent to dark current for degradation checks on the energy storage unit 2 when the vehicle is not started and the vehicle start signal S1 is not received. Thus, degradation checks on the energy storage unit 2 can be performed without putting a burden on the vehicle battery. Furthermore, the on-board power supply unit 1 can perform degradation checks on the energy storage unit 2 in a state that is ready to respond to emergencies and where there are no obstacles to discharging power in an emergency, and if the energy storage unit 2 is degraded, the on-board power supply unit 1 can warn passengers of the degradation state and make them aware of the condition.

[0018] The configuration and operation of the on-board power supply unit 1 will be described in detail below using the circuit block diagrams in Figures 1, 2, 3, and 4, which show the configuration of a vehicle equipped with the on-board power supply unit 1 according to an embodiment of the present invention.

[0019] The in-vehicle power supply device 1 mounted on the vehicle body 6 of the vehicle 5 can receive power supply from the vehicle battery 7 through the input terminal 8 of the in-vehicle power supply device 1. Also, the in-vehicle power supply device 1 can supply power to the vehicle load 10 through the output terminal 9 of the in-vehicle power supply device 1. Here, the vehicle load 10 corresponds to a door unlock motor, a shift change motor, and the like. Even if the vehicle battery 7 fails when the vehicle 5 encounters an unexpected situation, the vehicle load 10 can operate to ensure the safety of the vehicle 5 and the passengers by temporarily supplying power from the in-vehicle power supply device 1. Detection of the vehicle 5 encountering an unexpected situation may be carried out by an emergency signal transmitted by a vehicle body control unit (not shown) of the vehicle 5, or by the voltage of the vehicle battery 7 dropping to an abnormal value below the threshold during startup of the vehicle 5. When the vehicle 5 is in a normal state, the vehicle load 10 can operate by receiving power supply from the vehicle battery 7 through the normal conductor path 11.

[0020] The in-vehicle power supply device 1 includes a power storage unit 2, a charge and discharge circuit 3, a control unit 4, an input terminal 8, and an output terminal 9. The charge and discharge circuit 3 has a charge circuit 12 and a discharge circuit 13. The charge circuit 12 is connected to the input terminal 8 and the power storage unit 2. The charge circuit 12 can charge the power storage unit 2 with the power of the vehicle battery 7. The discharge circuit 13 is connected to the output terminal 9 and the power storage unit 2. The discharge circuit 13 can discharge and supply the power stored in the power storage unit 2 to the vehicle load 10.

[0021] The control unit 4 can detect the voltage stored in the power storage unit 2 and the current flowing through the charge circuit 12 and the discharge circuit 13. The current flowing through the charge circuit 12 and the discharge circuit 13 is detected using the voltage output from a Hall element arranged in the charge circuit 12 and the discharge circuit 13. Alternatively, the current flowing through the charge circuit 12 and the discharge circuit 13 is detected using the potential difference generated at both ends of a shunt resistor arranged in the charge circuit 12 and the discharge circuit 13.

[0022] Furthermore, the start signal transmitting unit 14 mounted on the vehicle body 6 transmits a vehicle start signal S1 when the vehicle 5 is starting, and the control unit 4 can receive the vehicle start signal S1. The start signal transmitting unit 14 may also be a vehicle body control unit (not shown) or a vehicle start switch (not shown) of the vehicle 5. The control unit 4 can also transmit a warning signal S2 to a warning display unit 15 mounted on the vehicle body 6.

[0023] Here, we will describe the operation of the control unit 4 when the vehicle 5 is in a normal state (vehicle 5 is not encountering any unforeseen circumstances, and the vehicle battery 7 is not in a failure state and is able to output power normally). First, when the occupant starts the vehicle 5 at TG0, the vehicle control unit (not shown) transmits a vehicle start signal S1. At this time, the vehicle battery 7 is normally able to supply power to the vehicle load 10 through the conductor path 11, and the vehicle battery 7 is also able to supply power to the onboard power supply unit 1.

[0024] At TG0, the control unit 4 receives the vehicle start signal S1 and activates the charging circuit 12 to begin charging the energy storage unit 2. Prior to TG0, when the vehicle 5 was not started, the energy storage unit 2 was charged at an initial voltage V0 that would not easily cause deterioration in the energy storage unit 2. Then, when the charging circuit 12 starts operating at TG0, a charging current IG0 flows through the charging circuit 12 from TG0 to TG1, and the energy storage unit 2 is charged, causing the voltage to rise from the initial voltage V0 to the first voltage V1. Here, the first voltage V1 should be a value that allows the vehicle load 10 to operate even if the vehicle battery 7 fails due to an unforeseen event in the vehicle 5, as mentioned earlier, by discharging the power stored in the energy storage unit 2 through the discharge circuit 13.

[0025] The period from TG0 to TG1 is very short; in other words, charging of the energy storage unit 2 is completed in a short time. From TG1 to T1, although basically no current flows through the charging circuit 12 or the discharging circuit 13, a small amount of power may be supplied to the energy storage unit 2 from the charging circuit 12 in order to maintain the first voltage in the energy storage unit 2.

[0026] Next, at time T1, the control unit 4 operates the discharge circuit 13 to discharge with the first current I1, thereby lowering the voltage of the energy storage unit 2 from the first voltage V1 to the second voltage V2. The voltage of the energy storage unit 2 becomes the second voltage V2 at time T2. The operation of the onboard power supply unit 1 during the period from time T1 to time T2 corresponds to the discharge mode. Here, the second voltage V2 is set to a lower value than the first voltage V1, but like the first voltage V1, the second voltage V2 should be a value that allows the power stored in the energy storage unit 2 to be boosted or lowered by the discharge circuit 13 even if the vehicle battery 7 fails when the vehicle 5 encounters an unforeseen situation, and that allows the vehicle load 10 to be operated by being discharged through the discharge circuit 13. Naturally, the second voltage V2 is a higher value than the initial voltage V0.

[0027] Next, at time T2, the control unit 4 operates the charging circuit 12 to charge with the second current I2, raising the voltage of the energy storage unit 2 from the second voltage V2 to the third voltage V3. The voltage of the energy storage unit 2 becomes the third voltage V3 at time T3. The operation of the onboard power supply unit 1 during the period from time T2 to time T3 corresponds to the charging mode. Here, the third voltage V3 is a higher value than the second voltage V2, and the third voltage V3 may be substantially the same value as the first voltage V1.

[0028] Here, as shown in Figure 2, we will explain the case where a stop period TS is provided during the period from T1 to T2 of the discharge mode to stop the discharge by the first current I1. The stop period TS corresponds to the period from time T11 to time T12.

[0029] The control unit 4 detects the shutdown voltage VS of the energy storage unit 2 during the shutdown period TS. The control unit 4 also detects the operating voltage V11, which is the voltage of the energy storage unit 2 immediately before the shutdown period TS, or the operating voltage V12, which is the voltage of the energy storage unit 2 immediately after the shutdown period TS. In other words, this corresponds to the operating voltage V11 at T11, the point at which the system switches from the state where the first current I1 is flowing to the shutdown period TS, or the operating voltage V12 at T12, the point at which the system switches from the shutdown period TS back to the state where the first current I1 is flowing again. The operating voltages V11 and V12 are substantially the same value as the operating voltage VD.

[0030] The control unit 4 then calculates the potential difference VP based on the stop period voltage VS and the operating voltage VD. Furthermore, the control unit 4 calculates the first internal resistance value R1, which is the internal resistance value of the energy storage unit 2, based on the potential difference VP and the first current I1. More specifically, the control unit 4 first calculates the potential difference VP, which is the difference between the stop period voltage VS and the operating voltage V11, or the difference between the stop period voltage VS and the operating voltage V12. Furthermore, the control unit 4 calculates the first internal resistance value R1, which is the value obtained by dividing the potential difference VP by the first current I1. Then, the control unit 4 compares the first internal resistance value R1 with the threshold resistance value RTH that has been stored in the control unit 4 beforehand. If the first internal resistance value R1 is greater than or equal to the threshold resistance value RTH, the control unit 4 determines that the energy storage unit 2 is deteriorating. When the control unit 4 determines that the energy storage unit 2 is deteriorating, the control unit 4 sends a warning signal S2 to the warning display unit 15 to warn passengers and others that the energy storage unit 2 is in a deteriorating state.

[0031] Here, it is desirable that the energy storage unit 2 uses an electric double-layer capacitor or a lithium-ion capacitor capable of discharging at a high current density. As electric double-layer capacitors and lithium-ion capacitors degrade, their internal resistance increases, leading to a decrease in energy storage capacity. Therefore, the internal resistance value corresponding to the limit of energy storage capacity degradation should be set as the threshold resistance value (RTH).

[0032] This section describes the case where a stop period TS is provided during the period T1 to T2 of the discharge mode to stop discharge by the first current I1. On the other hand, the stop period TS may also be provided in the charge mode. As shown in Figure 3, we will now describe the case where a stop period TS is provided during the period T2 to T3 of the charge mode to stop discharge by the second current I2. The stop period TS corresponds to the period from time T21 to time T22.

[0033] The control unit 4 detects the shutdown voltage VS of the energy storage unit 2 during the shutdown period TS. The control unit 4 also detects the operating voltage V21, which is the voltage of the energy storage unit 2 immediately before the shutdown period TS, or the operating voltage V22, which is the voltage of the energy storage unit 2 immediately after the shutdown period TS. In other words, this corresponds to the operating voltage V21 at T21, the point at which the system switches from the state where the first current I1 is flowing to the shutdown period TS, or the operating voltage V22 at T22, the point at which the system switches from the shutdown period TS back to the state where the first current I1 is flowing again. The operating voltages V21 and V22 are substantially the same value as the operating voltage VD.

[0034] The control unit 4 then calculates the potential difference VP based on the stop period voltage VS and the operating voltage VD. Furthermore, the control unit 4 calculates the second internal resistance value R2, which is the internal resistance value of the energy storage unit 2, based on the potential difference VP and the second current I2. More specifically, the control unit 4 first calculates the potential difference VP, which is the difference between the stop period voltage VS and the operating voltage V21, or the difference between the stop period voltage VS and the operating voltage V22. Furthermore, the control unit 4 calculates the first internal resistance value R1, which is the value obtained by dividing the potential difference VP by the second current I2. Then, the control unit 4 compares the second internal resistance value R2 with the threshold resistance value RTH that has been stored in the control unit 4 beforehand. If the second internal resistance value R2 is greater than or equal to the threshold resistance value RTH, the control unit 4 determines that the energy storage unit 2 is deteriorating. When the control unit 4 determines that the energy storage unit 2 is deteriorating, the control unit 4 sends a warning signal S2 to the warning display unit 15 to warn passengers and others that the energy storage unit 2 is in a deteriorating state.

[0035] Here, the control unit 4 may perform either one or both of the following: a degradation determination of the energy storage unit 2 when the stop period TS is set in discharge mode, and a degradation determination of the energy storage unit 2 when the stop period TS is set in charge mode. Furthermore, if the control unit 4 obtains different determinations when both the discharge mode and the charge mode are performed, the control unit 4 may perform both the discharge mode and the charge mode again.

[0036] With the above configuration and operation, the on-board power supply unit 1 can perform degradation determination of the energy storage unit 2 when it receives the vehicle start signal S1, in other words, when the vehicle equipped with the on-board power supply unit 1 is started, while the on-board power supply unit 1 is operational. For this reason, when the vehicle is not started and the vehicle start signal S1 is not received, the on-board power supply unit 1 does not require power equivalent to dark current to perform degradation determination of the energy storage unit 2. Thus, the control unit 4 can perform degradation determination of the energy storage unit 2 without burdening the vehicle battery 7. Furthermore, the on-board power supply unit 1 can perform degradation determination of the energy storage unit 2 while the energy storage unit 2 is in an emergency-ready state with the necessary power stored, and consumes power at a level that does not cause problems when discharging power in an emergency. If the energy storage unit 2 is degraded, the on-board power supply unit 1 can warn passengers of the degradation status as needed, making them aware of the condition.

[0037] Here, the period from the time TG0 when the passenger starts the vehicle 5, or from the subsequent time TG1, to the time T1 when the discharge mode is executed, may be a time set in advance by the control unit 4. Alternatively, the time T1 may not be set simply by time, but the control unit 4 may be made capable of detecting the amount of traveled by the vehicle 5, and the time T1 may be set after the control unit 4 detects that the vehicle 5 has traveled a predetermined amount of travel.

[0038] The above-mentioned mileage should be set based on the condition that the onboard power supply unit 1, and especially the energy storage unit 2, will reach a temperature similar to that of ambient temperature or normal use as a result of the vehicle 5 running. This provides the control unit 4 with appropriate conditions for determining the degradation of the energy storage unit 2. In other words, the control unit 4 can perform degradation determination of the energy storage unit 2 in discharge mode and charge mode with high reliability.

[0039] Furthermore, it is preferable that the control unit 4 performs the degradation of the energy storage unit 2 in discharge mode or charge mode when the vehicle is stopped at an intersection or similar location, in other words, when the vehicle 5 has stopped moving after starting. At this time, the control unit 4 is naturally capable of detecting when the vehicle 5 has stopped moving. Here, the control unit 4 may set the time point T1 when it has detected that the vehicle 5 has stopped moving after receiving the vehicle start signal S1 when the vehicle 5 has started. Alternatively, the control unit 4 may set the time point T1 when it has detected that the vehicle 5 has stopped moving after receiving the vehicle start signal S1 when the vehicle 5 has started, and after the control unit 4 has detected that the vehicle 5 has traveled a predetermined distance.

[0040] This allows the control unit 4 to determine the deterioration of the energy storage unit 2 after consuming power from the storage unit 2 at a time when the vehicle 5 is stationary, which is less likely to encounter accidents or other unforeseen circumstances compared to when it is in motion, and when the onboard power supply unit 1 is less likely to be needed. Naturally, since the vehicle 5 is running, the burden on the vehicle battery 7 due to the consumption of dark current and other factors can be suppressed.

[0041] When the control unit 4 operates the discharge circuit 13 in discharge mode and discharges the first current I1, the discharged power should be supplied to the vehicle load 10. The discharge mode starts at T1 when the vehicle 5 is already in a running state. In this case, since the vehicle 5 is in a normal running state, many other vehicle loads 10 are running in addition to the vehicle load 10 that ensures the safety of the vehicle 5 and its occupants in the event of a failure of the vehicle battery 7. Therefore, by supplying discharge power to the running vehicle loads 10, the occurrence of failures in the discharge circuit 13 due to excessive current flow in the discharge circuit 13 is suppressed, and the on-board power supply unit 1 can maintain high reliability.

[0042] When the control unit 4 operates the discharge circuit 13 in discharge mode and discharges the first current I1, the discharged power may be supplied to the vehicle battery 7. Since the vehicle battery 7 is larger than the capacity of the energy storage unit 2, it can be easily charged by the power discharged from the discharge circuit 13. Here, the path for supplying power from the discharge circuit 13 to the vehicle battery 7 may normally use the conductive path 11. Alternatively, the path for supplying power from the discharge circuit 13 to the vehicle battery 7 may be a discharge path (not shown) inside the onboard power supply unit 1 that connects the output section and the input terminal 8 of the discharge circuit 13.

[0043] The first current I1 and the second current I2 may be constant current values ​​except during the stop period TS. The charging current IG0 may also be a constant current value. Furthermore, the first current I1 and the second current I2 may be smaller values ​​than the charging current IG0. Moreover, the period from TG0 to TG1 during which the charging current IG0 flows may be shorter than the period from T1 to T2 during which the first current I1 flows, and the period from T2 to T3 during which the second current I12 flows.

[0044] Furthermore, the change from the first voltage V1 to the second voltage V2, and from the second voltage V2 to the third voltage V3, is a much slower and smaller rate of change compared to the change from the initial voltage V0 to the first voltage V1 from TG0 to TG1. As a result, the operating voltages V11, V12, V21, and V22 detected at the point when the voltage of the energy storage unit 2 becomes discontinuous or close to a discontinuous state can be accurately detected by the control unit 4, and consequently, the accuracy of the determination regarding the degradation of the energy storage unit 2 is also improved.

[0045] In the operation curve diagrams in Figures 2 and 3 above, the initial voltage V0 used for explanation corresponds to the case where the energy storage unit 2 is charged at a very low voltage before TG0, that is, before the vehicle 5 starts up. Furthermore, the setting of a small initial voltage V0 was achieved by the discharge operation of an electrical circuit (not shown) and a discharge circuit 13 provided in the energy storage unit 2 to discharge any unnecessary power from the energy storage unit 2 when the vehicle 5 starts up or stops.

[0046] On the other hand, the initial voltage V0 may be set to be equivalent to the first voltage V1 or the third voltage V3, or to be higher than the first voltage V1 or the third voltage V3, before TG0. In other words, the setting of the initial voltage V0 should be set according to the characteristics of the energy storage element used in the energy storage unit 2. In this case as well, the second voltage V2 should be a value that can be boosted or lowered by the discharge circuit 13, or a value that can operate the vehicle load 10 by being discharged through the discharge circuit 13.

[0047] The control unit 4 described above is an element that has the functions of receiving and transmitting signals, controlling circuits, storing data, and performing calculations. The above functions do not necessarily have to be provided as a single element, the control unit 4 may be configured to encompass individual functions that are distributed. [Industrial applicability]

[0048] The in-vehicle power supply device of the present invention has the effect of being able to determine the deterioration of the energy storage unit without consuming dark current, and is useful in various types of vehicles. [Explanation of Symbols]

[0049] 1 In-vehicle power supply 2. Energy Storage Unit 3 Charge / discharge circuit 4. Control Unit 5 vehicles 6. Car body 7. Vehicle Battery 8 Input terminals 9 Output terminal 10 Vehicle load 11 Normal Conductor 12 Charging circuit 13 Discharge circuit 14. Startup signal generator 15 Warning display section

Claims

1. A power storage unit; a charge / discharge circuit capable of charging / discharging the power storage unit and discharging power from the power storage unit in an emergency; a control unit capable of detecting a voltage of the power storage unit and a current flowing through the charge / discharge circuit, receiving a vehicle start signal, and transmitting a warning signal; The control unit When the vehicle activation signal is received, a discharge mode in which the charge / discharge circuit performs a discharge operation with a first current to reduce the voltage of the power storage unit from a first voltage to a second voltage; Furthermore, in a charging mode, the charging / discharging circuit is operated to charge with a second current, thereby increasing the voltage of the power storage unit from the second voltage to a third voltage; a stop period during which the discharging operation or the charging operation is stopped is provided in at least one of the charging mode and the discharging mode; The control unit detecting a potential difference between a stop period voltage of the power storage unit during the stop period and an operating voltage of the power storage unit immediately before or after the stop period; When the stop period is set in the discharge mode, a first resistance value is obtained by the potential difference and the first current, When the stop period is set in the charging mode, a second resistance value is obtained by the potential difference and the first current; issuing the warning signal when the first resistance value or the second resistance value is equal to or greater than a threshold resistance value; In-vehicle power supply.

2. The control unit is further capable of detecting a predetermined travel distance, After the control unit receives the vehicle start signal and further detects the predetermined traveling distance, or after a predetermined time has elapsed since receiving the vehicle start signal, detecting a potential difference between a stop period voltage of the power storage unit during the stop period and an operating voltage of the power storage unit immediately before or after the stop period; When the stop period is set in the discharge mode, a first resistance value is obtained by the potential difference and the first current, When the stop period is set in the charging mode, a second resistance value is obtained by the potential difference and the first current; issuing the warning signal when the first resistance value or the second resistance value is equal to or greater than a threshold resistance value; The vehicle-mounted power supply device according to claim 1 .

3. The control unit is further capable of detecting a traveling stop state, When the control unit detects the traveling stop state after receiving the vehicle start signal, The control unit detecting a potential difference between a stop period voltage of the power storage unit during the stop period and an operating voltage of the power storage unit immediately before or after the stop period; When the stop period is set in the discharge mode, a first resistance value is obtained by the potential difference and the first current, When the stop period is set in the charging mode, a second resistance value is obtained by the potential difference and the first current; issuing the warning signal when the first resistance value or the second resistance value is equal to or greater than a threshold resistance value; The vehicle-mounted power supply device according to claim 1 .

4. the charge / discharge circuit includes a charge circuit that charges the power storage unit with power, and a discharge circuit that discharges the power storage unit with power, The control unit the power output from the discharge circuit when the discharge circuit discharges at a first current in the discharge mode is returned to the charge circuit, thereby reducing the voltage of the power storage unit from a first voltage to a second voltage; The vehicle-mounted power supply device according to claim 1 .

5. The discharge circuit is operated to discharge at a first current in the discharge mode, and the output power is supplied to a vehicle load. The vehicle-mounted power supply device according to claim 1 .

6. The discharge circuit is operated to discharge at a first current in the discharge mode, and the output power is supplied to a vehicle battery. The vehicle-mounted power supply device according to claim 1 .

7. the control unit causes the charge / discharge circuit to perform a charging operation when the vehicle start signal is received, and charges the vehicle battery to the first voltage using power from the vehicle battery. The vehicle-mounted power supply device according to claim 1 .

8. the first current in the discharge mode is a constant current; the second current in the charging mode is a constant current; The vehicle-mounted power supply device according to claim 1 .

9. The first voltage and the second voltage are a value higher than a voltage corresponding to the power output from the power storage unit via the charge / discharge circuit and capable of driving a load; The vehicle-mounted power supply device according to claim 1 .

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