JP4884031B2 - Vehicle power supply system - Google Patents

Description

  The present invention relates to a vehicular power supply system that uses a plurality of power storage devices in combination, and more particularly to a vehicular power supply system that has a function of detecting an internal state of a plurality of power storage devices.

Conventionally, a battery remaining capacity estimation method for estimating a battery remaining capacity is known (see, for example, Patent Document 1). This battery remaining capacity estimation method is a method for estimating the remaining capacity of a battery mounted on a vehicle based on current and voltage fluctuations during discharging to a starter that starts the engine.
JP 2004-42799 A

  By the way, although a power supply system for a vehicle using a plurality of power storage devices such as a battery has recently appeared, a power storage device that does not supply a starting current to a starter that starts the engine when the engine is started among the plurality of power storage devices. The internal state such as the remaining capacity cannot be estimated with the above-described prior art.

  Therefore, the present invention provides a vehicle power supply having a function of estimating the internal state of a plurality of power storage devices used together as an in-vehicle power supply regardless of whether or not the starter for starting the engine is a power storage device that provides a starting current. The purpose is to provide a system.

In order to solve the above problems, as the present invention,
A first power storage device;
A second power storage device;
Voltage conversion means;
A starter for starting the engine of the vehicle,
The first power storage device is connected to the starter, and the second power storage device is connected to the starter via the voltage converter,
The voltage conversion direction of the voltage conversion means when power is supplied to the starter is set in the direction from the second power storage device side to the starter side,
An internal state estimation unit is provided that estimates an internal state of the first and second power storage devices based on a power supply state of the first and second power storage devices when power is supplied to the starter. A vehicle power supply system is provided.

  Here, in setting the power supply state suitable for detecting the internal state of the second power storage device, the voltage conversion unit adjusts the power supply amount from the second power storage device side to the first power storage device side. Further, the voltage conversion means may limit the power supply amount in accordance with a predetermined restriction condition that defines that power supply is restricted with respect to a power supply state of the second power storage device. Is preferred.

  In addition, examples of the power supply state of the first and second power storage devices include a current state, a voltage state, and a temperature state, and the internal state includes a charge state, a deterioration state, and a charge / discharge capacity. The first power storage device and the second power storage device may be different voltage systems.

  According to the present invention, it is possible to estimate the internal states of a plurality of power storage devices that are used together as an in-vehicle power source regardless of whether or not the power storage device supplies start current to a starter that starts the engine.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of a vehicle power supply system of the present invention. A vehicle on which the vehicle power supply system of the present invention is mounted includes a battery A that is a power storage device of a voltage system having a predetermined voltage value (hereinafter referred to as “A voltage system”) and a voltage system having a predetermined voltage value (hereinafter referred to as “voltage system”). A battery B that is a power storage device of “B voltage system” and a voltage conversion mode (hereinafter referred to as “voltage conversion mode”) that converts the voltage of the A voltage system into the voltage of the B voltage system and supplies power from the A voltage system to the B voltage system. , “A / B conversion mode”) and a voltage conversion mode (hereinafter referred to as “B / A”) that converts the voltage of the B voltage system to the voltage of the A voltage system and supplies power from the B voltage system to the A voltage system. A DC / DC converter 30 having a conversion mode and a stop mode in which voltage conversion is stopped and power is not supplied, and an electronic control unit 40 (hereinafter referred to as “ECU 40”) that controls the DC / DC converter 30. I have. Note that the DC / DC converter 30 and the ECU 40 may be integrated.

  There may be a case where a plurality of electric loads exist on the vehicle and electric loads of different voltage systems coexist. The battery A mainly corresponds to the power supply to the electric load 50 that operates with the voltage of the A voltage system, and the battery B Corresponds mainly to the power supply to the electric load 60 that operates with the voltage of the B voltage system. Specific examples of the battery A and the battery B include a lead battery, a lithium ion battery, a nickel metal hydride battery, and an electric double layer capacitor. The battery A and the battery B may be a combination of any of a lead battery, a lithium ion battery, a nickel metal hydride battery, and an electric double layer capacitor.

  The DC / DC converter 30 is voltage conversion means for performing voltage conversion between an input voltage and an output voltage. The DC / DC converter 30 converts the input voltage on the battery A side (starter 3 side described later) into a voltage by using a voltage conversion mechanism inside the DC / DC converter 30 such as a transformer, a switching regulator, or a series regulator. Or input voltage on the battery B side is converted to voltage and output to the battery A side (starter 3 side). The converted output voltage is monitored by the ECU 40 or a converter control circuit inside the DC / DC converter 30 and controlled so that the output voltage becomes constant. The DC / DC converter 30 converts an input voltage on the battery A side into an A / B conversion mode for outputting the voltage to the battery B side, and B / A for converting the input voltage on the battery B side into a voltage and outputting it to the battery A side. Of the conversion mode and the stop mode in which voltage conversion is stopped and voltage output is not performed, one of the modes is set during operation. By using the voltage conversion function of the DC / DC converter 30, the input voltage on the battery A side can be converted to supply power to the electric load 60 or charge the battery B. It is possible to convert the input voltage on the B side to supply power to the electric load 50 and the starter 3 or to charge the battery A, and stop voltage conversion and do not supply power. Is possible.

  The DC / DC converter 30 adjusts its output current to a desired value when supplying power from one to the other. When the DC / DC converter 30 does not exist, for example, in FIG. 1, the battery A and the battery B are simply connected in parallel. In this case, however, battery A and battery B (electric load 50 and electric load 60) cannot be set to different voltage systems, and the current flowing from one battery to the other cannot be controlled. Current will flow through. However, the presence of the DC / DC converter 30 allows the battery A and the battery B (the electric load 50 and the electric load 60) to be set to different voltage systems, and the current adjustment function of the DC / DC converter 30 The current flowing from one battery to the other battery can be controlled.

  The battery A is connected to a generator 1 that generates electric power by converting kinetic energy into electric energy via an A voltage system power line 19. The generator 1 generates electric power by the output of the engine 70 for running the vehicle. The electric power generated by the generator 1 is supplied to the electric load 50 or the battery A is charged. In the A / B conversion mode, supply to the electric load 60 and charging to the battery B can be performed via the DC / DC converter 30. A specific example of the generator 1 is an alternator. As the rotational speed of the engine 70 increases, the power generation amount of the alternator also increases. Since charging to the battery A and the like can be performed by regenerating the motor (electric motor), the generator 1 may be a motor capable of regenerative control. For example, in order to secure the braking force of the vehicle, regenerative control of a motor connected to the wheel drive shaft can charge the battery A via the inverter or supply electric power to the electric load 50. You can do it.

  Further, when the generator 1 is stopped, power can be supplied from the battery B to the electric load 50. For example, the electric power required in the parking state where the engine 70 is stopped and the alternator is inoperative can be supplied from the battery B to the electric load 50.

  Further, a starter 3 for starting the engine 70 is connected to the battery A via the A voltage system power supply line 19. Since the starter 3 needs to start the stopped engine 70 by cranking, it is necessary to supply a large operating current (starting current) to the starter 3 when the starter 3 is started. The starter 3 is, for example, an electric motor.

  When an operation signal for starting the starter 3 is input, the starter 3 is energized, and the pinion gear of the starter 3 and the ring gear of the flywheel of the engine 70 are engaged (connected). Thereby, when the starter 3 rotates, the crankshaft of the engine 70 rotates via the flywheel, and the engine 70 starts. When an operation signal for stopping the starter 3 is input (when an operation signal for starting the starter 3 is not input), the pinion gear of the starter 3 and the ring gear of the flywheel of the engine 70 are separated from each other and are not energized. Thus, the rotation of the starter 3 is stopped.

  The ECU 40 calculates the charge / discharge current value of the battery A based on the output value of the current sensor 4a that detects the charge / discharge current (battery current) of the battery A, and detects the charge / discharge current (battery current) of the battery B. The charge / discharge current value of the battery B is calculated based on the output value of the sensor 4b. Further, the ECU 40 calculates the voltage value of the battery A based on the output value of the voltage sensor 5a that detects the voltage of the battery A, and the voltage of the battery B based on the output value of the voltage sensor 5b that detects the voltage of the battery B. Calculate the value. As is clear from FIG. 1, the voltage of the battery A or the voltage of the battery B is a voltage of the A voltage system power supply line 19 or the B voltage system power supply line 29 and is applied to the electric load 50 or the electric load 60. Corresponds to the voltage. Further, the ECU 40 calculates the temperature of the battery A based on the output value of the temperature sensor 6a that detects the temperature of the battery A, and determines the temperature of the battery B based on the output value of the temperature sensor 6b that detects the temperature of the battery B. calculate.

  The ECU 40 estimates the internal states of the battery A and the battery B by calculating the discharge current, voltage, temperature, and other states of the battery A and the battery B when supplying power to the starter 3 as described above. The internal state includes a so-called deterioration state (SOH) indicating a deterioration degree, a state of charge (SOC) indicating a remaining capacity, and a charge / discharge capacity.

  ECU 40 estimates the deterioration state of batteries A and B according to the degree of battery voltage drop when engine 70 is started. When the engine 70 starts, a very large current (also referred to as an inrush current) flows from the battery to the starter 3 at a normal time. Therefore, if the high battery voltage is maintained even if the inrush current flows, the battery deteriorates. If the high battery voltage cannot be maintained, the battery can be regarded as deteriorated. Therefore, the ECU 40 estimates, as an example of a method for estimating the deterioration state of the battery, that the battery is deteriorated when the minimum value of the battery voltage that drops at the initial stage of discharge when supplying power to the starter 3 is equal to or less than a predetermined threshold. To do. Note that the ECU 40 may determine that the battery is deteriorated when the time until the battery voltage that drops at the initial stage of discharging when supplying power to the starter 3 drops to a predetermined voltage is equal to or shorter than a predetermined time. That is, the deterioration state of the battery is determined by measuring the discharge duration until the battery voltage reaches a predetermined voltage when a large current is passed. It can be considered that the longer the discharge duration, the less the deterioration.

  In addition, ECU 40 estimates the state of charge of batteries A and B according to the degree of battery voltage drop when engine 70 is started. The ECU 40 calculates a minimum value of the battery voltage when the engine 70 is started in order to estimate the state of charge of the batteries A and B. Since it is known that there is a correlation between the minimum value of the battery voltage that drops at the initial stage of discharge when supplying power to the starter 3 and the state of charge, the ECU 40 is based on the correlation (for example, map data). The state of charge can be estimated.

  The ECU 40 may estimate the state of charge of the batteries A and B by measuring the internal resistances of the batteries A and B at the initial stage of discharging when supplying power to the starter 3. The internal resistance can be calculated based on the relationship between the measured initial discharge current and the initial discharge voltage. Since it is known that the internal resistance and the state of charge have a correlation, the ECU 40 can estimate the state of charge based on the correlation (for example, map data).

  The batteries A and B have temperature characteristics, and internal states such as a deterioration state, a charge state, and a charge / discharge capacity vary depending on the temperature. Therefore, the ECU 40 refers to the actual temperature data of the batteries A and B and the temperature characteristics of the batteries A and B, and corrects the internal state such as the charge state, the deterioration state, and the charge / discharge capacity, thereby improving the accuracy. .

  Although details will be described later, the ECU 40 outputs a control signal for controlling the mode switching of the DC / DC converter 30 and the output voltage and output current based on predetermined conditions.

  The ECU 40 includes a plurality of ROMs such as a ROM for storing control programs and control data, a RAM for temporarily storing control program processing data, a CPU for processing control programs, and an input / output interface for exchanging information with the outside. It is composed of circuit elements. The ECU 40 is not limited to one control unit, and may be a plurality of control units so that control is shared.

  Now, the operation of the first embodiment of the vehicle power supply system of the present invention will be described with reference to FIGS. FIG. 4 is an example of a state transition diagram of the DC / DC converter 30. FIG. 5 is an example of an operation sequence of the first embodiment of the vehicle power supply system of the present invention.

  The ECU 40 acquires the operating state of the starter 3, and when the “starter operating flag” indicating the operating state of the starter 3 changes from OFF to ON, the control state of the DC / DC converter 30 is changed from “parking state”. The state is changed to “Eng (engine) start state” (FIGS. 5B and 5C). The DC / DC converter 30 that has made a transition to the Eng start state changes the operation mode from the stop mode to the B / A conversion mode, thereby starting power supply from the battery B side to the battery A side (FIG. 5 ( d), (e)).

  The ECU 40 calculates states such as the discharge currents, voltages, and temperatures of the batteries A and B when the control state of the DC / DC converter 30 is in the Eng start state, so that the deterioration state, capacity state, and charge / discharge capacity of the batteries A and B are calculated. Estimate the internal state. Since power is supplied from the battery B side to the battery A side by setting the B / A conversion mode in the Eng start state, power is supplied from both the batteries A and B to the starter 3. It will be. At this time, the ECU 40 distributes the power supply amount to the starter 3 to the batteries A and B at a desired distribution ratio by adjusting the output current of the DC / DC converter 30 set to the B / A conversion mode. can do. For example, when the amount of current to be supplied to the starter 3 is 500 A, if the limit value of the output current from the battery B side to the battery A side by the DC / DC converter 30 is adjusted to 100 A, a current of 400 A is output from the battery A. While being supplied to the starter 3, a current of 100 A is supplied from the battery B to the starter 3.

  Then, the ECU 40 acquires information on the rotational speed of the engine 70, and when the "Eng rotational flag" indicating the rotational operation state of the engine 70 changes from OFF to ON as the rotational speed of the engine 70 increases to a predetermined value. Then, the control state of the DC / DC converter 30 is changed from the “Eng start state” to the “Eng rotation state” (FIGS. 5A, 5C, and 5F). The DC / DC converter 30 that has transitioned to the Eng rotation state changes the operation mode from the B / A conversion mode to the A / B conversion mode, thereby supplying power from the battery B side to the battery A side. To supply power to the battery B (FIGS. 5D and 5E). The “starter operating flag” changes from ON to OFF when the starter 3 is stopped.

  Then, the ECU 40 acquires information on the rotational speed of the engine 70, and when the rotational speed of the engine 70 drops to a predetermined value (or when the rotational speed of the engine 70 stops), the Eng rotation flag is turned from ON to OFF. When the state changes to, the control state of the DC / DC converter 30 is changed from the “Eng rotation state” to the “parking state”. The DC / DC converter 30 that has made a transition to the parking state changes the operation mode from the A / B conversion mode to the stop mode, thereby ending the power supply by stopping the voltage conversion.

  Therefore, according to the first embodiment of the vehicle power supply system of the present invention, the operation mode of the DC / DC converter 30 is set to the B / A conversion mode when the engine is started, so that it is supplied to the starter 3 when the engine is started. The electric power to be supplied can be supplied not only from the battery A directly connected to the starter 3 but also from the battery B via the DC / DC converter 30. Therefore, not only the battery A directly connected to the starter 3 but also the battery B not directly connected to the starter 3 can estimate the internal state by discharging a large amount of power.

  Further, according to the first embodiment of the vehicle power supply system of the present invention, the DC / DC converter 30 is used even if the battery B is a power storage device that does not supply the starting current to the starter 3 when the engine 70 is started. Thus, it is possible to supply power from the battery B to the starter 3. Therefore, it is possible to estimate the internal state by discharging a large amount of power even with respect to the battery B that does not supply the starting current to the starter 3 when the engine 70 is started. Note that the power storage device that does not supply the starting current to the starter 3 when the engine 70 is started is a power storage device that does not have a discharge capability for operating the starter 3 in advance, or the starting current cannot be supplied to the starter 3 in advance. It means a power storage device having a configuration.

  According to the first embodiment of the vehicle power supply system of the present invention, the power supply state such as the discharge current and voltage of the battery A and the battery are adjusted by adjusting the output current of the DC / DC converter 30 when the engine is started. The power supply state such as the discharge current and voltage of B can be adjusted so as to be as optimal as possible for the estimation of the internal state. Since it is difficult to estimate the internal state of the battery unless there is a certain amount of discharge from the battery, it is difficult to estimate the internal state of the battery A if the discharge current from the battery A to the starter 3 is too small. This is because if the discharge current from the battery B to the starter 3 is too small, it is difficult to estimate the internal state of the battery B.

  Further, according to the first embodiment of the vehicle power supply system of the present invention, power is supplied to the starter 3 from both the batteries A and B, so that the engine 70 is started by the discharge current from only the battery A. In comparison, the start time of the engine 70 is shortened, which contributes to an improvement in the startability of the engine 70.

  FIG. 2 is a configuration diagram showing a second embodiment of the vehicle power supply system of the present invention. In the second embodiment, the description of the same reference numerals and functions as those in the first embodiment is omitted or simplified. In the second embodiment shown in FIG. 2, the starter 3 is connected to the battery B side with respect to the DC / DC converter 30, and the generator 1 and the starter 3 are connected via the DC / DC converter 30. Has been.

  The DC / DC converter 30 according to the second embodiment converts the input voltage on the battery A side into a voltage on the battery B side (by the voltage conversion mechanism inside the DC / DC converter 30 such as a transformer, a switching regulator, or a series regulator). Output to the starter 3 side), or convert the input voltage on the battery B side (starter 3 side) to output to the battery A side. By using the voltage conversion function of the DC / DC converter 30, the input voltage on the battery A side may be converted to supply power to the electric load 60 or the starter 3 or charge the battery B. It is possible to convert the input voltage on the battery B side to supply power to the electric load 50 or charge the battery A, and stop voltage conversion and do not supply power. Is possible.

  The operation of the second embodiment of the vehicular power supply system of the present invention will now be described with reference to FIGS. FIG. 6 is an example of an operation sequence of the second embodiment of the vehicle power supply system of the present invention.

  The ECU 40 acquires the operating state of the starter 3, and when the “starter operating flag” indicating the operating state of the starter 3 changes from OFF to ON, the control state of the DC / DC converter 30 is changed from “parking state”. State transition is made to “Eng (engine) start state” (FIGS. 6B and 6C). The DC / DC converter 30 that has transitioned to the Eng start state changes the operation mode from the stop mode to the A / B conversion mode, thereby starting power supply from the battery A side to the battery B side (FIG. 6 ( d), (e)).

  The ECU 40 calculates states such as the discharge currents, voltages, and temperatures of the batteries A and B when the control state of the DC / DC converter 30 is in the Eng start state, so that the deterioration state, capacity state, and charge / discharge capacity of the batteries A and B are calculated. Estimate the internal state. Since power is supplied from the battery A side to the battery B side because the A / B conversion mode is set in the Eng start state, power is supplied from both the batteries A and B to the starter 3. It will be. At this time, the ECU 40 distributes the power supply amount to the starter 3 to the batteries A and B at a desired distribution ratio by adjusting the output current of the DC / DC converter 30 set to the A / B conversion mode. can do.

  Then, the ECU 40 acquires information on the rotational speed of the engine 70, and when the "Eng rotational flag" indicating the rotational operation state of the engine 70 changes from OFF to ON as the rotational speed of the engine 70 increases to a predetermined value. Then, the control state of the DC / DC converter 30 is changed from the “Eng start state” to the “Eng rotation state” (FIGS. 6A, 6C, and 6F). The DC / DC converter 30 that has made a transition to the Eng rotation state may continue to supply power from the battery A side to the battery B side with the operation mode set to the A / B conversion mode (FIG. 6 (d), (E)). The “starter operating flag” changes from ON to OFF when the starter 3 is stopped.

  As in the first embodiment, the ECU 40 changes the operation mode from the A / B conversion mode to the stop mode by changing the operation mode from the A / B conversion mode to the parking state. The power supply is terminated by stopping the conversion.

  Therefore, according to the second embodiment of the vehicle power supply system of the present invention, the operation mode of the DC / DC converter 30 is set to the A / B conversion mode when the engine is started, so that the power is supplied to the starter 3 when the engine is started. The power to be supplied can be supplied not only from the battery B directly connected to the starter 3 but also from the battery A via the DC / DC converter 30. Therefore, not only the battery B directly connected to the starter 3 but also the battery A not directly connected to the starter 3 can estimate the internal state by discharging a large amount of power.

  Further, according to the second embodiment of the vehicle power supply system of the present invention, the DC / DC converter 30 is used even if the battery A is a power storage device that does not supply the starting current to the starter 3 when the engine 70 is started. By this, it becomes possible to supply electric power from the battery A to the starter 3. Accordingly, it is possible to estimate the internal state by discharging a large amount of power even with respect to the battery A that does not supply the starting current to the starter 3 when the engine 70 is started.

  Further, according to the second embodiment of the vehicle power supply system of the present invention, as in the first embodiment, the discharge current of the battery A is adjusted by adjusting the output current of the DC / DC converter 30 when the engine is started. The power supply state such as voltage and voltage and the power supply state such as discharge current and voltage of the battery B can be adjusted to be as optimal as possible for estimation of the internal state.

  Further, according to the second embodiment of the vehicle power supply system of the present invention, the power is supplied from both the batteries A and B to the starter 3 as in the first embodiment. Since the start time of the engine 70 is shortened compared to the start time of the engine 70 due to the discharge current, it contributes to improvement of the startability of the engine 70.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, FIG. 3 is a block diagram showing a third embodiment of the vehicle power supply system of the present invention. In the third embodiment, the description of the same reference numerals and functions as those in the first embodiment is omitted or simplified. In the third embodiment shown in FIG. 3, the generator 1 and the starter 3 of the first embodiment shown in FIG. 1 are replaced with an MG (so-called starter generator) 2. The MG 2 has both the function of the generator 1 and the function of the starter 3. Therefore, in the third embodiment, the MG 2 is directly connected to the MG 2 in the same manner as in the first embodiment by operating in the same operation sequence as in FIG. 5 according to the state transition diagram of the DC / DC converter 30 shown in FIG. It is possible to estimate the internal state by discharging a large amount of power not only for the connected battery A but also for the battery B that is not directly connected to MG2. Further, it is possible to estimate the internal state of the battery B that does not supply the starting current to the MG 2 when the engine 70 is started by discharging a large amount of power.

  Further, according to the third embodiment of the vehicle power supply system of the present invention, the discharge current of the battery A is adjusted by adjusting the output current of the DC / DC converter 30 when starting the engine, as in the first embodiment. The power supply state such as voltage and voltage and the power supply state such as discharge current and voltage of the battery B can be adjusted to be as optimal as possible for estimation of the internal state.

  Further, according to the third embodiment of the vehicle power supply system of the present invention, as in the first embodiment, power is supplied from both the batteries A and B to the MG 2, so that the startability of the engine 70 is improved. To contribute.

  By the way, the relationship between the voltage values of the A voltage system and the B voltage system described above may be the same value or different values, and the present invention is not particularly limited to the voltage values of the respective voltage systems. Even if the voltage values of the voltage system on the battery A side and the voltage system on the battery B side are the same, it is possible to perform voltage conversion by the DC / DC converter 30 as in the above-described embodiment. That is, similarly to the effect of the above-described embodiment, it is possible to estimate the internal state by discharging a large amount of power not only for the battery directly connected to the starter 3 but also for the battery not directly connected to the starter 3. It becomes possible to estimate the internal state by discharging a large amount of power even with respect to the battery that does not supply the starting current to the MG 2 when the engine 70 is started. Further, the power supply state such as the discharge current and voltage of the battery A and the power supply state such as the discharge current and voltage of the battery B can be adjusted so as to be as optimal as possible for the estimation of the internal state. Since electric power is supplied from both A and B, it contributes to improvement of the startability of the engine 70.

  Furthermore, in the above-described embodiment, the ECU 40 estimates the internal state of the batteries A and B, but an ECU such as a power management ECU other than the ECU 40 may estimate the internal state of the batteries A and B, If a sensor such as the sensor 4 has a calculator, the calculator may estimate the internal state of the batteries A and B.

It is a lineblock diagram showing a 1st embodiment of a power supply system for vehicles of the present invention. It is a block diagram which shows 2nd Embodiment of the vehicle power supply system of this invention. It is a block diagram which shows 3rd Embodiment of the power supply system for vehicles of this invention. 3 is an example of a state transition diagram of a DC / DC converter 30. FIG. It is an example of the operation | movement sequence of 1st and 3rd embodiment of the vehicle power supply system of this invention. It is an example of the operation | movement sequence of 2nd Embodiment of the power supply system for vehicles of this invention.

Explanation of symbols

1 Generator 2 MG
3 Starter 30 DC / DC converter 40 ECU
50, 60 Electric load 70 Engine A, B Battery

Claims (1)

A first power storage device;
A second power storage device;
Voltage conversion means;
A starter for starting the engine of the vehicle,
The first power storage device is connected to the starter, and the second power storage device is connected to the starter via the voltage converter,
The voltage conversion direction of the voltage conversion means when power is supplied to the starter is set in the direction from the second power storage device side to the starter side,
An internal state estimating means for estimating an internal state of the first and second power storage devices based on a power supply state of the first and second power storage devices when power is supplied to the starter;
Power supply from the second power storage device side to the starter side so that the amount of power supplied to the starter is distributed to the first power storage device and the second power storage device at a desired distribution ratio The vehicle power supply system is characterized in that the amount is adjusted by adjusting a limit value of an output current of the voltage converting means.

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