CN117734615A - Vehicle power supply system - Google Patents

Abstract

The invention provides a vehicle power supply system, which aims to estimate the state of a power supply supplying power to a functional part. The vehicle power supply system includes a vehicle power supply control device that measures the internal resistance of the 2 nd low-voltage power supply to estimate whether or not the vehicle power supply system is in a degraded state. The vehicle power supply control device is capable of executing a 1 st estimation process in which the internal resistance of the 2 nd low-voltage power supply when charging the 2 nd low-voltage power supply is measured, and a 2 nd estimation process in which the estimation is performed based on the discharge power from the 2 nd low-voltage power supply, and in which the 2 nd estimation process is executed when the high-voltage power supply unit of the vehicle power supply system is in an on state and the 1 st power supply system is in a state in which power is supplied from the high-voltage power supply unit and the state of the vehicle satisfies a predetermined condition.

Description

Vehicle power supply system

Technical Field

The present invention relates to a vehicle power supply system.

Background

In recent years, developments have become active to provide for the use of sustainable transportation systems that take care of people in a fragile standpoint among transportation participants. In order to achieve this object, research and development have been conducted to further improve traffic safety and convenience by research and development related to preventive safety. In addition, as one of technologies contributing to preventive safety, research and development related to automatic driving are being pursued.

In a vehicle equipped with a functional unit that functions to ensure traffic safety, such as automatic driving, it is important to stabilize the supply of power to such a functional unit. Accordingly, a technique for monitoring the state of a vehicle power supply with high accuracy has been proposed. For example, patent document 1 discloses a technique for determining a degradation state of a battery mounted on a vehicle by estimating the state of charge of the battery.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2019-152551

Disclosure of Invention

Problems to be solved by the invention

The technique of estimating the state of the battery mounted on the vehicle is susceptible to the state of the vehicle. For example, in the technique described in patent document 1, the state of charge is estimated on the condition that the temperature of the battery is lower than a threshold value. Thus, the following problems exist: depending on the state of the vehicle, it is difficult to estimate or determine the state of the battery with high accuracy. Therefore, there is a possibility that the battery state cannot be confirmed without a problem, and therefore, the problem is a problem when a functional unit for ensuring traffic safety is mounted on a vehicle.

In order to solve the above-described problems, an object of the present invention is to estimate a state of a power source supplying electric power to a functional unit by a method that is not easily affected by a vehicle state in a vehicle equipped with the functional unit functioning to ensure traffic safety, such as automatic driving. But also to facilitate the development of sustainable transportation systems.

Means for solving the problems

One embodiment for achieving the above object is a vehicle power supply system configured by mounting a 1 st power supply system, a 2 nd power supply system, and a high-voltage power supply unit on a vehicle, the 1 st power supply system having a 1 st low-voltage power supply and a 1 st electric load, the 2 nd power supply system having a 2 nd low-voltage power supply and a 2 nd electric load and being connected to the 1 st power supply system, the high-voltage power supply unit being capable of outputting a voltage higher than a rated voltage of the 1 st power supply system or the 2 nd power supply system, wherein the 2 nd power supply system includes: a switching device capable of switching between a state in which the switching device is connected to the 1 st power supply system so that power can be supplied from the 2 nd low-voltage power supply to the 1 st power supply system, and a state in which the switching device cuts off the 2 nd low-voltage power supply from the 1 st power supply system; and a vehicle power supply control device that controls the switching device, the vehicle power supply control device being capable of executing an estimation process of measuring an internal resistance of the 2 nd low-voltage power supply to estimate whether or not the 2 nd low-voltage power supply is in a degraded state, and outputting a signal indicating whether or not the 2 nd low-voltage power supply is in a degraded state as the estimation process based on an estimation result of the estimation process, the vehicle power supply control device being capable of executing: a 1 st estimation process of estimating an internal resistance of the 2 nd low-voltage power supply when the 2 nd low-voltage power supply is charged; and a 2 nd estimation process of estimating based on the discharge power from the 2 nd low-voltage power supply, wherein the vehicle power supply control device executes the 2 nd estimation process when the high-voltage power supply portion of the vehicle power supply system is in an on state, and when the high-voltage power supply portion supplies power to the 1 st power supply system, and when the state of the vehicle satisfies a predetermined condition.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the above configuration, the degradation state of the 2 nd low-voltage power supply that can supply power to the 1 st electric load and the 2 nd electric load can be estimated with high accuracy by a method that is not easily affected by the vehicle state.

Drawings

Fig. 1 is a schematic configuration diagram of a vehicle power supply system according to an embodiment.

Fig. 2 is an explanatory diagram of the estimation process in the vehicle power supply system.

Fig. 3 is an explanatory diagram of the estimation process in the vehicle power supply system.

Fig. 4 is a flowchart showing the operation of the vehicle power supply system.

Fig. 5 is a flowchart showing the operation of the vehicle power supply system.

Fig. 6 is an explanatory diagram showing an example of execution timing of the state detection operation.

Description of the reference numerals

1: vehicle power supply system, 10: power supply system, 11: main low voltage power supply, 12: normal load, 20: backup power supply system, 21: backup power supply unit, 22: critical load in emergency, 23: standby low voltage power, 24: switching device, 25: backup power control device, 30: high voltage power supply system, 31: high voltage power supply, 32: high voltage load, 36: high voltage power supply section, 40: step-down device, 50: ECU,55: operation unit, 56: SSSW,241: switch module, 321: drive unit, 322: air conditioner, CP: capacitor, MG: rotating electrical machine, PCU: power control unit, SW1: 1 st switch, SW2: 2 nd switch, SW3: 3 rd switch, V: a vehicle.

Detailed Description

An embodiment of a vehicle power supply system according to the present invention will be described below with reference to the drawings.

[1. Structure of vehicle Power supply System ]

[1-1. Overall structure of vehicle Power supply System ]

Fig. 1 is a schematic configuration diagram of a vehicle power supply system 1. In fig. 1, a solid line represents a power line, and a broken line represents a signal line.

The vehicle power supply system 1 of the vehicle V in the present embodiment includes a main power supply system 10, a backup power supply system 20 connected to the main power supply system 10, a high-voltage power supply system 30, and a step-down device 40. The high-voltage power supply system 30 is connected to the main power supply system 10 and the backup power supply system 20 via a step-down device 40. The step-down device 40 steps down the electric power flowing through the high-voltage power supply system 30, and outputs the electric power to the main power supply system 10 and/or the backup power supply system 20. The step-down device 40 is, for example, a DC/DC converter.

In the present embodiment, a description will be given of a case where the vehicle V is an electric vehicle provided with the rotating electrical machine MG as a power source for running, as an example. The rotating electrical machine MG is, for example, a 3-phase motor, and generates driving force by electric power supplied from an inverter unit, not shown, to run the vehicle V. The vehicle V includes a drive unit 321, and the drive unit 321 includes a rotating electrical machine MG described later. The vehicle V is mounted with a high-voltage power source 31 that supplies driving power to the driving unit 321. The driving unit 321 is a load that receives the supply of high-voltage power output from the high-voltage power supply 31, and is included in a high-voltage load 32 described later.

The vehicle V may be a vehicle on which an internal combustion engine is mounted. The internal combustion engine may also function as a power source for driving the vehicle V. Alternatively, the internal combustion engine may function as a power source for driving a generator, not shown, and charge a high-voltage power source 31, which will be described later. That is, the vehicle V may be an electric vehicle that does not include an internal combustion engine, a hybrid vehicle that includes an internal combustion engine and a rotating electrical machine MG for driving the vehicle, or a vehicle that is driven by the internal combustion engine. The vehicle V is, for example, a vehicle capable of autonomous driving or automatic driving. In the case where the vehicle V is equipped with an internal combustion engine, the high-voltage load 32 that receives supply of electric power from the high-voltage power source 31 includes, for example, a starter motor.

[1-2. Structure of Main Power System ]

The main power supply system 10 has a main low voltage power supply 11 and a normal load 12.

The main voltage source 11 is a power source having a voltage lower than that of the high voltage power source 31. The main power supply 11 outputs, for example, a direct current of 12 v. The main low-voltage power supply 11 is, for example, a secondary battery that can be charged and discharged. Specifically, as the main low-voltage power source 11, a lead battery, a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries may be mentioned.

The main low-voltage power supply 11 is disposed on the connection line L11. One end of the connection line L11 is connected to the contact C11 formed on the connection line L10, and the other end is connected to the ground line having the reference potential of the vehicle power supply system 1. The positive side of the main low-voltage power supply 11 is connected to the contact C11 side of the connection line L11, and the negative side is connected to the ground side of the connection line L11.

The load 12 is typically connected to one end of the connection line L10. The normal load 12 (EL in the drawing) is an electric load mounted on the vehicle V. Typically, load 12 may be a single device or may comprise multiple devices. In the present embodiment, the normal load 12 is a functional unit that is responsible for a function related to the running of the vehicle V. The normal load 12 includes, for example, a load responsible for functions related to a running operation, a parking operation, or a driving control of the vehicle V. The load 12 generally operates at a lower voltage than the high voltage load 32, and therefore can be referred to as a low voltage load by comparison with the high voltage load 32. In addition, the normal load 12 may also include equipment called an auxiliary machine in the vehicle V.

Specifically, the normal load 12 includes an ECU 50 (Electronic Control Unit: electronic control unit) capable of executing driving control of the vehicle V. The ECU 50 shown in fig. 1 may be constituted by one ECU or may include a plurality of ECUs. For example, the normal load 12 may include a part of a plurality of ECUs provided in the vehicle V. The normal load 12 may include a control unit, not shown, mounted on the vehicle V, which is different from the ECU 50.

The normal load 12 may include an auxiliary load for braking the vehicle V, such as an automatic braking device. The normal load 12 may include an auxiliary load for steering the vehicle V, such as an automatic steering device. The normal load 12 may include an auxiliary load such as LiDAR (Light Detection And Ranging: light detection and ranging) for acquiring external information of the vehicle V. The load 12 may include a wiper device, a power window device, a dashboard, or the like.

1-3 Structure of Standby Power supply System

The backup power supply system 20 includes a backup power supply unit 21 and an emergency critical load 22.

The backup power supply unit 21 includes a backup power supply 23, a switching device 24, and a backup power supply control device 25 that controls the switching device 24.

The standby power supply unit 21 includes a 1 st external connection terminal T211, a 2 nd external connection terminal T212, and a ground terminal T213. The other end of the connection line L10 is connected to the 1 st external connection terminal T211. The ground terminal T213 is connected to ground.

The emergency important load 22 (EL in the figure) is an electric load mounted on the vehicle V. The emergency critical load 22 may be a single device or may include a plurality of devices. The critical load 22 operates at a lower voltage than the high-voltage load 32 in the emergency, and therefore can be referred to as a low-voltage load in comparison with the high-voltage load 32.

The emergency important load 22 is connected to the 2 nd external connection terminal T212 of the backup power supply unit 21 via the connection line L21.

The switching device 24 includes a 1 st terminal T241, a 2 nd terminal T242, and a 3 rd terminal T243. The 1 st terminal T241 is connected to the 1 st external connection terminal T211 of the backup power supply unit 21 through a connection line L211. The 2 nd terminal T242 is connected to the 2 nd external connection terminal T212 of the backup power supply unit 21 through the connection line L212.

The switching device 24 includes a connection line L241 connecting the 1 st terminal T241 and the 2 nd terminal T242. The 1 st switch SW1 is provided on the connection line L241. In the present embodiment, the 1 st switch SW1 is a switch having a contact of a normally open type (n.o. type). That is, the 1 st switch SW1 is the following contact: when the operation signal is not applied to the 1 st switch SW1, the disconnection state is maintained, and the connection line L241 is maintained in the disconnection state. The 1 st switch SW1 is switched to an on state by an operation signal applied thereto, and connects the 1 st terminal T241 and the 2 nd terminal T242.

For example, in the case where the 1 st switch SW1 is configured by an electromagnetic switch that is opened and closed by electromagnetic force, the 1 st switch SW1 maintains an off state when electromagnetic force based on operation current is not generated, and maintains the connection line L241 in a disconnected state.

The 1 st switch SW1 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switching element, or may be a circuit such as a DC/DC converter having a switching function.

The switching device 24 includes a connection line L242 connecting the connection line L241 and the 3 rd terminal T243. One end of the connection line L242 is connected to the connection line L241 via a contact C241 formed between the 1 st switch SW1 and the 2 nd terminal T242 of the connection line L241, and the other end is connected to the 3 rd terminal T243.

The 2 nd switch SW2 is provided on the connection line L242. The 2 nd switch SW2 connects the connection line L242 in the on state and cuts off the connection line L242 in the off state.

The 2 nd switch SW2 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switching element, or may be a circuit such as a DC/DC converter having a switching function. In the present embodiment, the 2 nd switch SW2 is a DC/DC converter. Therefore, as will be described later, the 2 nd switch SW2 can step up and down the voltage output from the connection line L242 to the contact C241 in the on state. That is, the 2 nd switch SW2 of the present embodiment has a function of connecting and disconnecting the connection line L242 and a function of converting the voltage output from the connection line L242 to the contact C241.

The switching device 24 includes a connection line L243 connected in parallel with the connection line L241. One end of the connection line L243 is connected to a contact C242 of the connection line L241 formed between the 1 st terminal T241 and the 1 st switch SW 1. The other end of the connection line L243 is connected to a contact C243 of the connection line L241 formed between the contact C241 and the 2 nd terminal T242. The 3 rd switch SW3 is provided on the connection line L243.

In the present embodiment, the 3 rd switch SW3 is a switch having a normally-off (n.c. type) contact. That is, the 3 rd switch SW3 is the following contact: in the case where the operation signal is not applied to the 3 rd switch SW3, the on state is maintained. The 3 rd switch SW3 is switched to the off state by the application of the operation signal, and the connection line L243 is switched to the off state.

For example, in the case where the 3 rd switch SW3 is constituted by an electromagnetic switch that is opened and closed by electromagnetic force, the 3 rd switch SW3 maintains an on state when electromagnetic force based on operation current is not generated, and the connection line L243 maintains a connected state.

The 3 rd switch SW3 may be an electromagnetic switch such as an electromagnetic contactor, an electromagnetic switch, or a relay, or may be a semiconductor switching element, or may be a circuit such as a DC/DC converter having a switching function.

In the present embodiment, the 1 st switch SW1 and the 3 rd switch SW3 are modularized into a switch module 241. The specific structure of the switching module 241 is not limited, and for example, the switching module 241 may be 1 semiconductor device or may be a circuit including a plurality of devices.

The switching device 24 includes a connection line L244 connecting the connection line L241 with the ground line. One end of the connection line L244 is connected to a contact C244 of the connection line L241 formed between the 1 st switch SW1 and the contact C241. The other end of the connection line L244 is connected to the ground line. A capacitor CP is provided on the connection line L244.

The standby power supply 23 is a power supply having a voltage lower than that of the high-voltage power supply 31. The backup low-voltage power supply 23 outputs a direct current of, for example, 12 v. The backup low-voltage power supply 23 is, for example, a secondary battery that can be charged and discharged. Specifically, as the backup low-voltage power supply 23, a lead battery, a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries may be mentioned.

The standby low-voltage power supply 23 is provided to the connection line L213. One end of the connection line L213 is connected to the 3 rd terminal T243 of the switching device 24. The other end of the connection line L213 is connected to the ground line. The backup low-voltage power supply 23 is provided to the connection line L213 such that the positive electrode side is the 3 rd terminal T243 side of the switching device 24 and the negative electrode side is the ground line side.

When the 2 nd switch SW2 is in the on state, the backup low-voltage power supply 23 supplies electric power from the connection line L213 to the backup power supply system 20 through the connection line L242 of the switching device 24. The electric power output from the backup low-voltage power supply 23 is stepped up or down to a desired voltage by the 2 nd switch SW2, and is supplied to the backup power supply system 20. When the 2 nd switch SW2 is in the off state, the connection line L242 of the switching device 24 is in the off state, and therefore, no electric power is supplied from the backup low-voltage power supply 23 to the backup power supply system 20.

As described above, in the backup power supply system 20, the 1 st switch SW1 having a normally open contact and the 3 rd switch SW3 having a normally closed contact are connected in parallel between the 1 st terminal T241 and the 2 nd terminal T242.

When at least one of the 1 st switch SW1 and the 3 rd switch SW3 is in an on state, the backup power supply system 20 is connected to the main power supply system 10. In this state, the 1 st external connection terminal T211 can supply electric power from the backup low-voltage power supply 23 to the main power supply system 10, and can also supply electric power from the main low-voltage power supply 11 to the emergency critical load 22.

On the other hand, when both the 1 st switch SW1 and the 3 rd switch SW3 are in the off state, the connection between the backup power supply system 20 and the main power supply system 10 is disconnected.

The backup power supply control device 25 (BMS in the figure) is connected to the 1 st switch SW1, the 2 nd switch SW2 and the 3 rd switch SW3 via signal lines. The backup power supply control device 25 controls switching of the 1 st switch SW1, the 2 nd switch SW2 and the 3 rd switch SW3 in accordance with control of the ECU 50. The backup power supply control device 25 includes a processor such as a CPU (Central Processing Unit: central processing unit), and controls the backup power supply system 20 by cooperation of software and hardware by executing a program by the processor. In this case, the backup power supply control device 25 may include a storage unit for storing programs and data, and the storage unit may be, for example, a ROM (Read Only Memory). The backup power control 25 may also be comprised of programmed hardware.

The standby power control device 25 outputs operation signals to the 1 st switch SW1, the 2 nd switch SW2 and the 3 rd switch SW3 through signal lines, respectively. The standby power control device 25 can switch between a state in which the operation signal is output and a state in which the operation signal is not output with respect to the 1 st switch SW1, the 2 nd switch SW2, and the 3 rd switch SW3, respectively.

The 1 st switch SW1 is a normally open switch. The standby power control device 25 outputs an operation signal to the 1 st switch SW1 to switch the 1 st switch SW1 from the off state to the on state. The 3 rd switch SW3 is a normally-off switch. The backup power supply control device 25 outputs an operation signal to the 3 rd switch SW3 to switch the 3 rd switch SW3 from the on state to the off state.

The standby power control device 25 switches the 2 nd switch SW2 between the on state and the off state by outputting an operation signal to the 2 nd switch SW 2. Further, the standby power control device 25 controls the step-up or step-down in the 2 nd switch SW2 by outputting an operation signal to the 2 nd switch SW 2. That is, the standby power control device 25 controls the output voltage of the 2 nd switch SW 2.

The backup power supply control device 25 is operated by receiving power supply from the high-voltage power supply unit 36 or the backup low-voltage power supply 23, for example.

The backup power supply control device 25 has a function of managing the main power supply 11 and the backup low-voltage power supply 23. In the vehicle power supply system 1, a charge/discharge management device, not shown, may be mounted on the main low-voltage power supply 11. In this case, the backup power supply control device 25 may acquire information from the charge/discharge management device, and perform a management function for the main low-voltage power supply 11. Similarly, a charge/discharge management device, not shown, may be attached to the backup low-voltage power supply 23, and the backup power supply control device 25 may acquire information from the charge/discharge management device to perform a management function for the backup low-voltage power supply 23.

In the present embodiment, the configuration in which the backup power supply control device 25 is directly connected to the main low-voltage power supply 11 and the backup low-voltage power supply 23 will be described.

The backup power supply control device 25 obtains the remaining capacity of the main power supply 11. The backup power supply control device 25 may have a full Charge capacity (FCC: full Charge Capacity) Of the main low-voltage power supply 11, in which case the backup power supply control device 25 may calculate a State Of Charge (SOC: state Of Charge) Of the main low-voltage power supply 11 based on the actual remaining capacity (RM: remaining Capacity) Of the main low-voltage power supply 11 and the full Charge capacity. The backup power supply control device 25 may calculate the remaining capacity of the main low-voltage power supply 11 by detecting the voltage across the backup low-voltage power supply 23, for example. The backup power supply control device 25 may calculate the remaining capacity of the main low-voltage power supply 11 by counting the current input/output to/from the main low-voltage power supply 11. The backup power supply control device 25 may use the above-described charge/discharge management device for the process of calculating the remaining capacity of the main low-voltage power supply 11.

The backup power supply control device 25 has a function of estimating the degradation state of the backup low-voltage power supply 23, a function of detecting the temperature of the backup low-voltage power supply 23, and a function of calculating the remaining capacity of the backup low-voltage power supply 23. The remaining capacity may be the actual remaining capacity (RM) of the backup power supply 23 or may be the state of charge (SOC). The backup power supply control device 25 may have a Full Charge Capacity (FCC) of the backup low-voltage power supply 23, in which case the backup power supply control device 25 may calculate the state of charge based on the actual remaining capacity and full charge capacity of the backup low-voltage power supply 23.

The backup power supply control device 25 calculates the remaining capacity of the backup low-voltage power supply 23 by detecting the voltage across the backup low-voltage power supply 23, for example. The backup power supply control device 25 may calculate the remaining capacity of the backup low-voltage power supply 23 by counting the current input/output to/from the backup low-voltage power supply 23. The backup power supply control device 25 may use the above-described charge/discharge management device for the process of calculating the remaining capacity of the backup low-voltage power supply 23. The backup power supply control device 25 obtains the temperature of the backup low-voltage power supply 23 from a temperature detection device provided in the backup low-voltage power supply 23 or the charge/discharge management device described above.

The process of estimating the degradation state of the backup low-voltage power supply 23 by the backup power supply control device 25 is referred to as an estimation process. As a method for estimating or detecting the degradation state of the backup low-voltage power supply 23, various known methods can be used. In the present embodiment, as an estimation process, the backup power supply control device 25 executes an example of the 1 st estimation process in which the degradation state is estimated by measurement when the backup low voltage power supply 23 is charged, and the 2 nd estimation process in which the degradation state is estimated by measurement when the backup low voltage power supply 23 is discharged.

The 1 st estimation process and the 2 nd estimation process are, for example, methods of measuring the internal resistance value of the backup low-voltage power supply 23 and estimating the degradation state of the backup low-voltage power supply 23 based on the measured internal resistance value. The 1 st estimation process may be a process of correcting the degradation state by combining the internal resistance value of the backup low-voltage power supply 23 with other 1 or more pieces of information. Other information includes a remaining capacity, a state of charge, a temperature, an accumulated use time, an internal resistance value measured in the past, a use time since the internal resistance value was measured in the past, and the like of the backup low-voltage power supply 23, but information other than this may be used.

In the 1 st estimation process, the backup power supply control device 25 measures the internal resistance of the backup low-voltage power supply 23 while the backup low-voltage power supply 23 is being charged. In the 2 nd estimation process, the backup power supply control device 25 measures the internal resistance of the backup low voltage power supply 23 by using the discharge power of the backup low voltage power supply 23 while the backup low voltage power supply 23 is discharging. The backup power supply control device 25 selects which of the 1 st estimation process and the 2 nd estimation process is to be executed, according to the judgment of the backup power supply control device 25 or according to the instruction of the ECU 50.

In the above configuration, the main low-voltage power supply 11 corresponds to an example of the 1 st low-voltage power supply, the normal load 12 corresponds to an example of the 1 st electric load, and the main power supply system 10 corresponds to an example of the 1 st power supply system. The backup low-voltage power supply 23 corresponds to an example of the 2 nd low-voltage power supply, the emergency critical load 22 corresponds to an example of the 2 nd electric power load, and the backup power supply system 20 corresponds to an example of the 2 nd electric power supply system. The backup power supply control device 25 corresponds to an example of a vehicle power supply control device. As described above, the main low-voltage power supply 11 and the backup low-voltage power supply 23 are batteries that can be charged and discharged.

In the present embodiment, the emergency important load 22 is a functional unit that is responsible for a function related to the running of the vehicle V, and includes, for example, a load that is responsible for a function related to a running operation, a parking operation, or a driving control of the vehicle V. The emergency important load 22 includes a load responsible for a function for coping with an emergency while the vehicle V is traveling. Specifically, the emergency important load 22 includes a load responsible for the function related to the execution of the minimum risk policy (MRM: minimal Risk Maneuver) related to the running of the vehicle V. For example, the MRM includes an operation or control conforming to at least one of a minimum running operation, a parking operation, and a driving control required for safely moving the vehicle V to a shoulder of a road and parking the vehicle even if the driving force of the driving source is lost.

The emergency critical load 22 may include part or all of the aforementioned ECU 50 capable of executing driving control of the vehicle V. The emergency critical load 22 may include a control unit, not shown, mounted on the vehicle V, which is different from the ECU 50.

A part of the load included in the critical load 22 in the emergency may be repeated with the load included in the normal load 12 of the main power supply system 10. That is, a part of the normal load 12 may also become an emergency important load 22 belonging to both the main power supply system 10 and the backup power supply system 20. According to this structure, the emergency critical load 22 can be made redundant. In other words, the emergency critical load 22, which is overlapped with the normal load 12 of the main power supply system 10, can be operated by the electric power supplied to the main power supply system 10, or can be operated by the electric power supplied to the backup power supply system 20. Therefore, the emergency critical load 22, which is overlapped with the normal load 12 of the main power supply system 10, can operate even when an abnormality occurs in the main power supply system 10, and can operate even when an abnormality occurs in the backup power supply system 20.

When the 1 st switch SW1 or the 3 rd switch SW3 is turned on by the switching device 24, the backup power supply system 20 is connected to the main power supply system 10, and the backup low-voltage power supply 23 can supply electric power to the main power supply system 10. Therefore, the normal load 12 can be operated by the electric power of the backup low-voltage power supply 23.

1-4 Structure of high-voltage Power supply System

The high voltage power supply system 30 has a high voltage power supply 31 and a high voltage load 32.

The high-voltage power supply 31 is a power supply that supplies power of a higher voltage than the main low-voltage power supply 11 and the backup low-voltage power supply 23. The high-voltage power supply 31 is connected to the connection line L31. One end of the connection line L31 is connected to the ground, and the negative electrode side of the high-voltage power supply 31 is connected to the ground side of the connection line L31.

The high-voltage load 32 is an electric load that operates with a voltage higher than that of the normal load 12 and the emergency critical load 22, and operates with electric power supplied from the high-voltage power supply 31. In the present embodiment, the high-voltage load 32 includes a driving unit 321 that drives the vehicle V, and an air conditioning device 322 (a/C in the drawing) that performs air conditioning in the vehicle interior of the vehicle V.

The driving unit 321 includes a rotating electrical machine MG and a power control unit PCU that controls the rotating electrical machine MG. The power control unit PCU includes a DC/DC converter not shown, an inverter not shown, and the like.

The driving unit 321 is connected to the other end of the connection line L31. The drive unit 321 converts the direct-current power supplied from the high-voltage power source 31 into three-phase alternating-current power by the power control unit PCU, and supplies the three-phase alternating-current power to the rotating electrical machine MG. Thereby, the rotating electrical machine MG generates power for driving the vehicle V from the electric power of the high-voltage power source 31.

The air conditioner 322 is connected to the connection line L32, and the connection line L32 is connected to the connection line L31 through a contact C31 formed between the high-voltage power supply 31 of the connection line L31 and the driving unit 321. The air conditioner 322 operates by the electric power of the high-voltage power supply 31.

The voltage reducing device 40 is disposed on the connection line L40. One end of the connection line L40 is connected to the contact C32, and the other end is connected to the contact C12. The contact C32 is a contact formed between the high voltage power supply 31 and the contact C31 of the connection line L31. The contact C12 is a contact formed between the contact C11 of the connection line L10 and the other end portion of the connection line L10. Here, the other end portion of the connection line L10 corresponds to the 1 st external connection terminal T211 of the backup power supply system 20.

In this way, the high-voltage power supply system 30 is connected to the main power supply system 10 and the backup power supply system 20 via the step-down device 40.

The step-down device 40 steps down the electric power flowing in the high-voltage power supply system 30. The step-down device 40 is, for example, a DC/DC converter. The step-down device 40 steps down the voltage output from the high-voltage power supply system 30 and supplies the voltage to the main power supply system 10 and the backup power supply system 20.

The voltage reducing device 40 can switch between a connected state and a disconnected state. When the step-down device 40 is in the connected state, the high-voltage power supply system 30 is connected to the main power supply system 10 and the backup power supply system 20 via the connection line L40 and the step-down device 40. When the voltage reducing device 40 is in the off state, the high-voltage power supply system 30 is disconnected from the main power supply system 10 and the backup power supply system 20.

The high-voltage power supply 31 may be a power generation device mounted on the vehicle V or may be a battery mounted on the vehicle V. Examples of the battery include a secondary battery that can be charged and discharged. Specifically, a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, a metal hydride battery, or other batteries can be used as the high-voltage power supply 31. In this case, the high-voltage power supply 31 outputs, for example, 200 v.

In the case where the high-voltage power source 31 includes a secondary battery, the high-voltage power source 31 may include a power generation device that supplies electric power to the secondary battery. The high-voltage power supply 31 may be constituted by only a power generation device. As the power generation device, for example, a rotating electrical machine MG may be used. For example, the rotating electrical machine MG is caused to function as regenerative braking at the time of braking the vehicle V, and regenerative power generated by the rotating electrical machine MG can be used as the high-voltage power source 31. In addition, when the vehicle V is a vehicle having an internal combustion engine, the vehicle V is provided with a generator driven by the power of the internal combustion engine. The generator may be used as a high voltage power supply 31. The generator outputs the generated ac current through a boost circuit and a rectifying circuit, not shown. The ac current output from the generator may be supplied to the step-down device 40 directly or via a step-up circuit or a rectifier circuit, not shown.

The high-voltage power supply 31 and the step-down device 40 constitute a high-voltage power supply section 36. The high-voltage power supply 36 can output a voltage higher than the rated voltage of the backup power supply system 20. The high-voltage power supply 36 may be configured to output a voltage higher than the rated voltage of the main low-voltage power supply 11.

The high-voltage power supply 36 is constituted by, for example, a high-voltage power supply 31 constituted by a secondary battery and a step-down device 40. In the case where the high-voltage power supply 31 is configured by a generator driven by an internal combustion engine, a boost circuit and a rectifier circuit, not shown, connected to the generator may be used as components of the step-down device 40. That is, the high-voltage power supply unit 36 may be constituted by a generator and peripheral circuits thereof.

The high-voltage power supply 36 may be configured to perform a normal operation mode and a high-voltage mode. In this case, the high-voltage power supply unit 36 switches between the normal operation mode and the high-voltage mode in accordance with the control of the ECU 50. The normal operation mode is an operation mode for the purpose of supplying electric power to the normal load 12 and the emergency important load 22. The output voltage of the high-voltage power supply unit 36 in the normal operation mode is a voltage included in the range of the rated input voltages of the normal load 12 and the emergency important load 22. For example, in the vehicle V in which the rated output voltages of the main low-voltage power supply 11 and the backup low-voltage power supply 23 are 12[ V ], the high-voltage power supply unit 36 outputs a voltage in the range of 12[ V ] to 15[ V ] in the normal operation mode.

The high-voltage mode is an operation mode for the purpose of charging the standby low-voltage power supply 23 with electric power supplied from the high-voltage power supply unit 36. The output voltage of the high-voltage power supply 36 in the high-voltage mode is a voltage capable of charging the backup low-voltage power supply 23, and preferably a voltage capable of high-voltage charging of the backup low-voltage power supply 23.

In the normal operation mode, when the output voltage of the high-voltage power supply 36 is higher than the output voltage of the backup low-voltage power supply 23, the backup low-voltage power supply 23 is charged with the electric power of the high-voltage power supply 36. The high-voltage charging means the following operations: the state of charge of the backup low-voltage power supply 23 is increased in a short time as compared with the case where the backup low-voltage power supply 23 is charged in the normal operation mode. That is, the high-voltage charging means the following operations: the high-voltage power supply unit 36 operates in the high-voltage mode, and thereby the backup low-voltage power supply 23 is charged promptly. In the high voltage mode, the high voltage power supply section 36 outputs, for example, a voltage 2 times, 3 times, or more the normal operation mode.

The vehicle power supply system 1 may charge the main low-voltage power supply 11 by using the electric power output from the high-voltage power supply 36, similarly to the backup low-voltage power supply 23. In this case, if the voltage output from the high-voltage power supply unit 36 is higher than the output voltage of the main low-voltage power supply 11, the main low-voltage power supply 11 is charged. In the vehicle power supply system 1, when the high-voltage power supply 31 has a battery corresponding to high-voltage charging, the high-voltage power supply unit 36 may be operated in a high-voltage mode to perform high-voltage charging of the main low-voltage power supply 11 together with the backup low-voltage power supply 23.

The vehicle power supply system 1 includes an ECU 50. As described above, the ECU 50 may include a plurality of ECUs, or may be a single device. The ECU 50 corresponds to one example of a vehicle control device.

The ECU 50 is connected to the normal load 12, the emergency important load 22, the backup power supply control device 25, and the high-voltage load 32 via signal lines. The devices connected to the ECU 50 are not limited to the above-described portions. The ECU 50 may be connected to a device not shown in fig. 1 among the devices mounted on the vehicle V.

The ECU 50 includes, for example, a processor such as a CPU, and executes a program by the processor to control each part of the vehicle power supply system 1 by cooperation of software and hardware. In this case, the ECU 50 may include a memory unit for storing programs and data, and the memory unit may be, for example, a ROM. Furthermore, the ECU 50 may be constituted by programmed hardware.

The operation unit 55 is connected to the ECU 50. The operation unit 55 includes a switch or the like operated by a user of the vehicle V. For example, the operation portion 55 includes an SSSW (Start Stop SWitch: start-stop switch) 56 that is operated by a user to instruct the start and stop of the vehicle V. The operation unit 55 includes a switch or the like for a user to instruct the execution of autonomous driving of the vehicle V. The operation unit 55 may be a wireless communication device that is wirelessly connected to a remote control device, not shown, and detects an operation by the remote control device. Here, the user of the vehicle V is, for example, the driver of the vehicle V, but may include a person using the vehicle V other than the driver.

In the stopped state of the vehicle V, the vehicle power supply system 1 is turned off. In the off state of the vehicle power supply system 1, the ECU 50 is maintained in an operable state by the electric power supplied from the high-voltage power supply 31. The state may also be a state called a so-called sleep state or a low power consumption state. In the sleep state or the low power consumption state, the ECU 50 may be in a state in which, for example, the supply of electric power to some of the components of the ECU 50 is stopped. In the sleep state or the low power consumption state, the number of operation clocks of the ECU 50, the state of the ECU 50 detection operation unit 55, or the sampling frequency of the states of the various sensors may be set to a period longer than the period in which the vehicle V operates.

In the off state of the vehicle power supply system 1, electric power is supplied to the normal load 12 and the emergency critical load 22. This is to operate the emergency load 22 and the normal load 12 in the off state of the vehicle power supply system 1. For example, the ECU 50 monitors the detection value of a sensor included in the emergency load 22 or a sensor connected to the emergency load 22. For example, a function of monitoring the surroundings of the vehicle V in parking by a camera included in the emergency load 22 is performed. In such a case, the high-voltage power supply unit 36 supplies electric power to the emergency critical load 22 in order to operate the emergency critical load 22. The normal load 12 is similarly supplied with electric power from the high-voltage power supply 36. These powers are called so-called dark currents. Since the 3 rd switch SW3 is normally off as described above, even in a state where the backup power supply control device 25 is stopped, electric power can be supplied from the main power supply system 10 to the emergency critical load 22 via the 3 rd switch SW 3.

In the vehicle power supply system 1, electric power is supplied from the high-voltage power supply 31 to each part of the main power supply system 10 in a starting state of the vehicle V. Further, electric power is supplied from the high-voltage power supply unit 36 to the main power supply system 10 and the emergency critical load 22. In the stopped state of the vehicle V, as described above, the dark current flows from the high-voltage power supply portion 36 to the emergency critical load 22.

When a short circuit or a ground occurs in the main power supply system 10, the supply of electric power from the high-voltage power supply unit 36 to the emergency critical load 22 may be stopped in order to protect the vehicle power supply system 1. For example, fuses, not shown, are provided at a plurality of positions in a circuit constituting the vehicle power supply system 1. When the ground or short circuit occurs, fuses provided in the connection lines L31, L32, L40 and the like are cut, and the supply of electric power from the high-voltage power supply unit 36 to the emergency critical load 22 is stopped. Further, it is also possible to cause the voltage reducing device 40 to shut off the output by the protection function.

In this case, the vehicle power supply system 1 can also supply electric power from the backup low-voltage power supply 23 to the emergency critical load 22 so that the electric power supply to the emergency critical load 22 is not interrupted. This function implements a minimum risk strategy during autonomous driving of the vehicle V. Specifically, by switching the 2 nd switch SW2 on, the backup low-voltage power supply 23 is connected to the connection line L212, and power supply from the backup low-voltage power supply 23 to the emergency critical load 22 is started. Alternatively, the 2 nd switch SW2 may be turned on by the standby power control device 25 during the period in which the critical load 22 is operating in the emergency during the start of the vehicle V, and a power supply from the step-down device 40 to the standby power supply system 20 may be prepared. In this case, the output voltage of the 2 nd switch SW2 is adjusted in accordance with the output voltage of the step-down device 40 so that no current flows in the direction from the 2 nd switch SW2 toward the step-down device 40.

In order to implement the minimum risk strategy, the ECU 50 will be able to supply electric power to the emergency critical load 22 based on the backup low-voltage power source 23 as a condition for the vehicle V to perform autonomous driving.

The action state in which the vehicle V is performing autonomous driving is referred to as an autonomous driving mode. In the autonomous driving mode, the vehicle V travels in the autonomous driving mode at least without steering operation by the driver. That is, in the autonomous driving mode, the autonomous driving control unit 220 makes the vehicle V travel without requiring steering by the user by at least the lane keeping control unit 221 and the steering control unit 222. In the autonomous driving mode, the autonomous driving control portion 220 performs part of autonomous driving. The partial autonomous driving is to perform some of the functions related to autonomous driving, which the autonomous driving control unit 220 has, for example, steering by the lane keeping control unit 221 and the steering control unit 222, and may or may not include performing the autonomous driving functions by the brake control unit 223 and the travel control unit 224.

The ECU 50 executes autonomous driving of the vehicle V with an operation of the operation unit 55 or a preset operation state of the vehicle V as a trigger. That is, the autonomous driving mode of the vehicle V is started. In this case, the ECU 50 controls the autonomous driving control unit 220 to start autonomous driving. The ECU 50 also stops the autonomous driving of the vehicle V by triggering an operation of the operation unit 55 or a preset operation state of the vehicle V during the autonomous driving of the vehicle V. In this case, the ECU 50 controls the autonomous driving control unit 220 to end the autonomous driving mode and stop autonomous driving, and shifts to the normal running mode. The normal running mode is an operation mode in which steering by the user is required for running of the vehicle V.

The ECU 50 performs estimation of the degradation state of the backup low-voltage power supply 23 via the backup power supply control device 25. The backup power supply control device 25 outputs a signal based on the degradation state of the backup low-voltage power supply 23.

The standby power control device 25 performs signal output means: the backup power supply control device 25 outputs a signal indicating that autonomous driving of the vehicle V is permitted, and a signal indicating that autonomous driving of the vehicle V is prohibited. The output of these signals may be performed by the ECU 50 or another control device, but in the present embodiment, an example of the execution by the backup power supply control device 25 is described.

When the ECU 50 starts autonomous driving of the vehicle V, the backup power supply control device 25 executes estimation processing to determine whether or not the state of the backup low-voltage power supply 23 is sufficient for realizing the minimum risk policy, and the like. In each process including this determination, the backup power supply control device 25 refers to various thresholds as described below. These thresholds are held or stored in advance by the ECU 50 or the backup power supply control device 25.

When it is determined that the degradation state of the backup low-voltage power supply 23 is not appropriate, the backup power supply control device 25 outputs a signal indicating prohibition of autonomous driving of the vehicle V. This signal can be referred to as a disable signal, for example. The ECU 50 does not start autonomous driving when a prohibition signal is input from the backup power supply control device 25. Further, the ECU 50 ends the autonomous driving when a prohibition signal is input from the backup power supply control device 25 in the course of executing the autonomous driving of the vehicle V.

The backup power supply control device 25 outputs a signal indicating that autonomous driving of the vehicle V is permitted or a signal indicating that autonomous driving of the vehicle V is permitted to continue, in a case where it is determined that the available power of the backup power supply 23 is sufficient or in a case where the available power is not sufficient but can be recovered by charging. These signals can be referred to as enable signals, for example.

When the autonomous driving of the vehicle V is started, the ECU 50 starts the autonomous driving of the vehicle V on the condition that an permission signal is input from the backup power supply control device 25. Further, the ECU 50 continues the autonomous driving when an permission signal is input from the backup power supply control device 25 in the course of executing the autonomous driving of the vehicle V. The ECU 50 determines whether or not an permission signal is input from the backup power supply control device 25 every predetermined time while the autonomous driving of the vehicle V is being performed, and ends the autonomous driving when the state in which the permission signal is not input continues for a predetermined time or longer.

[2 ] operation of vehicle Power supply System ]

The operation of the vehicle power supply system 1 will be described.

Fig. 2 and 3 are explanatory diagrams of the estimation process in the vehicle power supply system 1. Fig. 2 shows the 1 st estimation process, and fig. 3 shows the 2 nd estimation process. The connection state of the main portions constituting the vehicle power supply system 1 is schematically shown in fig. 2 and 3.

In the state shown in fig. 2, the switching device 24 is turned on, and the backup power supply system 20 is connected to the high-voltage power supply unit 36. Specifically, the standby power control device 25 turns on at least one of the 1 st switch SW1 and the 3 rd switch SW3 of the switching device 24. In particular, it is preferable that the 1 st switch SW1 having a large current capacity is turned on. The 2 nd switch SW2 is turned on, and the standby low-voltage power supply 23 is connected to the switching device 24. In this state, the electric power output from the high-voltage power supply unit 36 is supplied to the emergency critical load 22. Further, the main low-voltage power supply 11 and the backup low-voltage power supply 23 are being charged with electric power supplied through the high-voltage power supply section 36.

In the 1 st estimation process, the backup power supply control device 25 measures or acquires the internal resistance value of the backup low-voltage power supply 23 in a state where the backup low-voltage power supply 23 is charged by the high-voltage power supply unit 36. The backup power supply control device 25 estimates the degradation state of the backup low voltage power supply 23 based on the internal resistance value of the backup low voltage power supply 23.

In the state shown in fig. 3, the switching device 24 is turned off, and the backup power supply system 20 and the high-voltage power supply unit 36 are disconnected. Specifically, the standby power control device 25 turns off both the 1 st switch SW1 and the 3 rd switch SW3 of the switching device 24. In this state, the high-voltage power supply unit 36 does not supply electric power to the emergency critical load 22 or the backup low-voltage power supply 23. Therefore, in the case where the emergency critical load 22 consumes power in the state shown in fig. 3, power is supplied from the backup low-voltage power supply 23 to the emergency critical load 22.

In the 2 nd estimation process, the backup power supply control device 25 measures or acquires the internal resistance value of the backup power supply 23 in a state where the backup low-voltage power supply 23 is discharged. The backup power supply control device 25 estimates the degradation state of the backup low voltage power supply 23 based on the internal resistance value of the backup low voltage power supply 23.

The 1 st estimation process has a feature that accuracy is lowered due to the state of the vehicle V and the influence of the environment. For example, when the temperature of the backup low-voltage power supply 23 is low, the internal resistance value of the backup low-voltage power supply 23 increases, and accordingly, the backup low-voltage power supply 23 needs to be charged with a high voltage. In the case where the temperature of the backup low-voltage power supply 23 is extremely low, the charging voltage of the backup low-voltage power supply 23 is high enough to reach the upper limit of the voltage allowed by the backup low-voltage power supply 23, and therefore, the detection accuracy of the internal resistance value may be lowered.

For example, when the remaining capacity of the main low-voltage power supply 11 is smaller than the remaining capacity of the backup low-voltage power supply 23, the electric power supplied by the high-voltage power supply 36 is often used for charging the main low-voltage power supply 11, and it is difficult to progress the charging of the backup low-voltage power supply 23. As a result, the internal resistance value of the standby low-voltage power supply 23 during charging may not be detected with high accuracy.

Further, the standby power supply 23 tends to increase in temperature due to charging. In order to protect the backup low-voltage power supply 23, it is desirable that charging is not performed when the temperature of the backup low-voltage power supply 23 is higher than a prescribed temperature.

In this way, depending on the state of the vehicle V, the accuracy of the 1 st estimation process may be lowered, or the 1 st estimation process may not be performed. In this case, the vehicle power supply system 1 estimates the degradation state of the backup low-voltage power supply 23 by performing the 2 nd estimation process.

Fig. 4 and 5 are flowcharts showing the operation of the vehicle power supply system 1. In the present embodiment, the operations of fig. 4 and 5 are executed by the backup power supply control device 25.

Fig. 4 shows a state detection operation including the backup power supply control device 25 estimating the degradation state of the backup low-voltage power supply 23.

The backup power supply control device 25 executes the estimation process at a predetermined timing (step S11). Step S11 will be described later with reference to fig. 5.

The backup power supply control device 25 determines whether or not the estimated value of the degradation state of the backup power supply 23 obtained by the estimation process is equal to or less than the 1 st threshold value (step S12). The estimated value of the degradation state of the standby power supply 23 can be said to be an estimated result. An estimated value of 1 st threshold or less means that the degradation state of the backup power supply 23 is lower than the appropriate range, and it can be said that the degradation of the backup power supply 23 is progressing.

When it is determined that the estimated value of the degradation state is equal to or less than the 1 st threshold (step S12; yes), the backup power supply control device 25 outputs a signal indicating that the backup power supply 23 is in the degradation state to the ECU 50 (step S13). In step S13, the backup power supply control device 25 may output a signal indicating that autonomous driving is not permitted to the ECU 50.

When it is determined that the estimated value of the degradation state is not equal to or less than the 1 st threshold (step S12; no), the backup power supply control device 25 outputs a signal indicating that the backup low-voltage power supply 23 is not in the degradation state to the ECU 50 (step S14). In step S14, the backup power supply control device 25 may also output a signal indicating that autonomous driving is permitted to the ECU 50.

Fig. 5 shows step S11 of fig. 4 in detail. In the operation described below, the 1 st temperature threshold corresponds to the 1 st temperature, and the 2 nd temperature threshold corresponds to the 2 nd temperature.

The backup power supply control device 25 determines whether or not the high-voltage power supply unit 36 is outputting electric power (step S21). The state in which the high-voltage power supply portion 36 is outputting electric power is a state in which the vehicle V is being started. When it is determined that the high-voltage power supply unit 36 is not outputting power (step S21; no), the backup power supply control device 25 ends the operations of fig. 4 and 5.

When it is determined that the high-voltage power supply unit 36 is outputting electric power (yes in step S21), the backup power supply control device 25 determines whether or not the main low-voltage power supply 11 is being charged (step S22). When it is determined that the main low-voltage power supply 11 is in charge (step S22; yes), the backup power supply control device 25 selects and executes the 2 nd estimation process (step S23). If the 1 st estimation process is performed during charging of the main low-voltage power supply 11, the measurement accuracy of the internal resistance value may be affected by insufficient charging current to the backup low-voltage power supply 23. Therefore, it is appropriate to perform the 2 nd estimation process.

In step S23, the standby power control device 25 turns off the 1 st switch SW1 and the 3 rd switch SW3 of the switching device 24 to operate the emergency critical load 22, and measures the internal resistance value of the standby power supply 23 during the operation of the emergency critical load 22. In step S23, the ECU 50 may control the emergency load 22 to operate. After obtaining the internal resistance value, the backup power supply control device 25 returns to the operation of fig. 4.

When it is determined that the main low-voltage power supply 11 is not being charged (step S22; no), the backup power supply control device 25 acquires the temperature TB of the backup low-voltage power supply 23 (step S24). The backup power supply control device 25 determines whether or not the temperature TB is equal to or less than the 1 st temperature threshold (step S25). When it is determined that temperature TB is equal to or less than the 1 st temperature threshold (step S25; yes), backup power supply control device 25 proceeds to step S23, and executes the 2 nd estimation process. The 1 st temperature threshold is a threshold indicating an extremely low temperature at which the internal resistance value is not suitable to be measured due to charging, and is, for example, -15[ deg.C ].

When it is determined that temperature TB is not equal to or less than the 1 st temperature threshold (step S25; no), backup power supply control device 25 determines whether temperature TB is equal to or greater than the 2 nd temperature threshold (step S26). When it is determined that temperature TB is equal to or higher than the 2 nd temperature threshold (step S26; yes), backup power supply control device 25 proceeds to step S23 to execute the 2 nd estimation process. The 2 nd temperature threshold is a threshold indicating a high temperature up to unsuitable for charging, and is, for example, 40[ deg. ].

When it is determined that temperature TB is not equal to or higher than the 2 nd temperature threshold (step S26; no), backup power supply control device 25 obtains the remaining capacity of main power supply 11 (RMA in this case) and the remaining capacity of the backup low-voltage power supply (RMB in this case) (step S27). The backup power supply control device 25 determines whether the remaining capacity RMA is smaller than the remaining capacity RMB (step S28). The remaining capacities RMA and RMB may be states of charge SOC obtained from the remaining capacities.

When it is determined that remaining capacity RMA is smaller than remaining capacity RMB (step S28; yes), backup power control device 25 proceeds to step S23, and executes the 2 nd estimation process. For example, when the vehicle V is not used for a long period of time, the remaining capacity of the main low-voltage power supply 11 may be reduced. If the 1 st estimation process is performed in a state where the remaining capacity of the main low-voltage power supply 11 is smaller than the remaining capacity of the backup low-voltage power supply 23, sufficient power may not be supplied to the backup low-voltage power supply 23 to charge the backup low-voltage power supply 23, and therefore, it is appropriate to perform the 2 nd estimation process.

When it is determined that remaining capacity RMA is not smaller than remaining capacity RMB (step S28; no), backup power control device 25 proceeds to step S29, and executes 1 st estimation processing (step S29). In step S29, the backup power supply control device 25 turns on the 1 st switch SW1 of the switching device 24, and measures the internal resistance value of the backup low-voltage power supply 23 during charging of the backup low-voltage power supply 23 from the high-voltage power supply unit 36. After obtaining the internal resistance value, the backup power supply control device 25 returns to the operation of fig. 4.

Fig. 6 is an explanatory diagram showing an example of execution timing of the state detection operation, and the horizontal axis shows passage of time. Fig. 6 (a) shows an operating state of the vehicle V, fig. 6 (b) shows a state of the high-voltage power supply unit 36, and fig. 6 (c) shows a state of the backup power supply system 20.

The time T1 is a timing at which an operation of the user of the vehicle V before the start of the vehicle V is detected in the stopped state of the vehicle V. The operation is, for example, release of a door lock of the vehicle V, remote control operation of the vehicle V, or the like.

The high-voltage power supply portion 36 stops the supply of electric power in the stopped state of the vehicle V. At time T1, the high-voltage power supply unit 36 is advanced by the control of the ECU 50. The advanced operation is to start the high-voltage power supply unit 36 and supply electric power before the normal load 12 or the emergency critical load 22 starts to operate. The advanced operation of the high-voltage power supply 36 is performed by control of the ECU 50 or the backup power supply control device 25, for example.

Next, at time T2, when the operation of SSSW56 is detected, vehicle power supply system 1 shifts vehicle V to the ignition-on state. In the vehicle V without the internal combustion engine, at time T2, the vehicle V shifts to the Ready state. The Ready state is a state in which the vehicle V can travel. The vehicle V runs in the ignition-on or Ready state according to the operation of the user. At time T2, the vehicle power supply system 1 performs power supply to each section based on the high-voltage power supply section 36.

In the ignition-on or Ready state, the vehicle power supply system 1 stops the vehicle V upon detecting that the SSSW56 is operated by the user. Here, the vehicle power supply system 1 extends the execution of the operation by the high-voltage power supply portion 36. The operation extension is to continue the power supply by the high-voltage power supply unit 36 for a predetermined time after the vehicle V is stopped. The time for which the operation is extended is predetermined, and the vehicle power supply system 1 ends the operation extension at time T4, and stops the high-voltage power supply unit 36.

The state detection operation of the vehicle power supply system 1 is performed, for example, between time T1 and time T2 and/or between time T3 and time T4. After time T2, since a large amount of current is supplied to the normal load 12 and the emergency critical load 22, there is a possibility that the current for charging the backup low-voltage power supply 23 cannot be sufficiently ensured. In contrast, when the state detection operation is performed between the time T1 and the time T2, a sufficient charging current can be ensured, and therefore, the degradation state of the backup low-voltage power supply 23 can be estimated with high accuracy. Further, by performing the state detection action before running the vehicle V, the degradation state of the backup power source 23 is estimated before starting autonomous driving, which has an advantage that information can be provided to the user as needed.

Further, for example, in the case where the time from the time T1 to the time T2 is short, it is possible to shift to the ignition-on or Ready state before the completion of the state detection action. In this regard, there is an advantage in performing the charge detection operation between the time T3 and the time T4. When the state detection operation is performed between the time T3 and the time T4, the vehicle power supply system 1 may omit the state detection operation when the vehicle V is started next. For example, the vehicle power supply system 1 may also perform the following control: by the ECU 50 executing the counting of the timer, the state detection operation can be omitted within a predetermined time after the execution of the state detection operation. In this case, the vehicle power supply system 1 may hold the estimation or determination result of the degradation state of the backup power supply 23 obtained by the state detection operation until the next vehicle V starts.

[3 ] other embodiments ]

The above embodiment shows a specific example of application of the present invention, and is not limited to the mode of application of the present invention.

For example, the method of estimating the available power of the backup low-voltage power supply 23 by the backup power supply control device 25 is not limited to the above-described method. For example, in the case where a power supply control device that manages and controls charging and discharging of the backup low-voltage power supply 23 is mounted to the backup low-voltage power supply 23, the power supply control device may estimate the available power at all times or at predetermined intervals. In this case, the backup power supply control device 25 may acquire an estimated value of the available power from the power supply control device of the backup power supply 23.

Fig. 1 shows an example, and for example, the step-down device 40 may be integrally formed with the high-voltage power supply 31, and the power that has been stepped up or stepped down by the step-down device 40 may be supplied to the high-voltage load 32. The timing chart shown in fig. 5 is merely an example of the operation, and the operation of the vehicle power supply system 1 can be appropriately changed.

[4 ] the Structure supported by the above embodiment ]

The above embodiment supports the following structure.

The vehicle power supply system according to the present invention is a vehicle power supply system according to the present invention, including a 1 st power supply system, a 2 nd power supply system, and a high-voltage power supply unit mounted on a vehicle, wherein the 1 st power supply system includes a 1 st low-voltage power supply and a 1 st power load, the 2 nd power supply system includes a 2 nd low-voltage power supply and a 2 nd power load, and is connected to the 1 st power supply system, and the high-voltage power supply unit is capable of outputting a voltage higher than a rated voltage of the 1 st power supply system or the 2 nd power supply system, wherein the 2 nd power supply system includes: a switching device capable of switching between a state in which the switching device is connected to the 1 st power supply system so that power can be supplied from the 2 nd low-voltage power supply to the 1 st power supply system, and a state in which the switching device cuts off the 2 nd low-voltage power supply from the 1 st power supply system; and a vehicle power supply control device that controls the switching device, the vehicle power supply control device being capable of executing an estimation process of measuring an internal resistance of the 2 nd low-voltage power supply to estimate whether or not the 2 nd low-voltage power supply is in a degraded state, and outputting a signal indicating whether or not the 2 nd low-voltage power supply is in a degraded state as the estimation process based on an estimation result of the estimation process, the vehicle power supply control device being capable of executing: a 1 st estimation process of estimating an internal resistance of the 2 nd low-voltage power supply when the 2 nd low-voltage power supply is charged; and a 2 nd estimation process of estimating based on the discharge power from the 2 nd low-voltage power supply, wherein the vehicle power supply control device executes the 2 nd estimation process when the high-voltage power supply portion of the vehicle power supply system is in an on state, and when the high-voltage power supply portion supplies power to the 1 st power supply system, and when the state of the vehicle satisfies a predetermined condition.

According to the configuration 1, in the configuration in which the 2 nd power load can be supplied with power by the 2 nd low-voltage power supply and the 1 st power supply system can be connected by the switching device, the 1 st power load can be supplied with power from the 2 nd low-voltage power supply, the degradation state of the 2 nd low-voltage power supply can be estimated with high accuracy. Accordingly, the deterioration state of the 2 nd low-voltage power supply can be estimated by a method that is not easily affected by the vehicle state, and therefore, a large number of opportunities for confirming the state of the 2 nd low-voltage power supply can be ensured. For example, it is possible to avoid a state in which the 1 st electric load and the 2 nd electric load cannot be operated because the state of the 2 nd low-voltage power supply cannot be confirmed.

(structure 2) the vehicle power supply system according to structure 1, wherein the predetermined condition includes that the temperature of the 2 nd low-voltage power supply is 1 st temperature or lower.

According to the configuration 2, even when it is difficult to estimate the internal resistance at the time of charging the 2 nd low-voltage power supply by using the low temperature of the 2 nd low-voltage power supply, the degradation state of the 2 nd low-voltage power supply can be estimated with high accuracy.

(structure 3) the vehicle power supply system according to structure 1 or 2, wherein the predetermined condition includes the temperature of the 2 nd low-voltage power supply being 2 nd temperature or higher.

According to the configuration 3, even in a case where the 2 nd low-voltage power supply is unsuitable for charging the 2 nd low-voltage power supply due to a high temperature, the degradation state of the 2 nd low-voltage power supply can be estimated with high accuracy.

(structure 4) the vehicle power supply system according to any one of structures 1 to 3, wherein the 1 st low-voltage power supply and the 2 nd low-voltage power supply are constituted by a battery that can be charged and discharged, and the prescribed condition includes that a remaining capacity of the battery of the 1 st low-voltage power supply is smaller than a remaining capacity of the battery of the 2 nd low-voltage power supply.

According to the configuration 4, even in a case where it is difficult to estimate the internal resistance at the time of charging the 2 nd low-voltage power supply by charging the 1 st low-voltage power supply, the degradation state of the 2 nd low-voltage power supply can be estimated with high accuracy.

(structure 5) the vehicle power supply system according to any one of structures 1 to 4, wherein the vehicle power supply control device, in a state where the switching device is turned off in a case where the 2 nd estimation process is performed, measures the internal resistance of the 2 nd low voltage power supply based on the discharge power discharged by the 2 nd low voltage power supply, thereby estimating whether the 2 nd low voltage power supply is in a degraded state.

According to the configuration 5, the 2 nd low-voltage power supply is disconnected from the 1 st power supply system, and the degradation state of the 2 nd low-voltage power supply can be estimated with high accuracy based on the discharge power of the 2 nd low-voltage power supply. Thus, the degradation state of the 2 nd low-voltage power supply can be estimated with high accuracy by a method that is not easily affected by the power consumption or the like of other circuits in the vehicle power supply system.

Claims (5)

1. A vehicle power supply system is constituted by mounting a 1 st power supply system, a 2 nd power supply system and a high-voltage power supply unit on a vehicle, wherein the 1 st power supply system has a 1 st low-voltage power supply and a 1 st electric load, the 2 nd power supply system has a 2 nd low-voltage power supply and a 2 nd electric load, and is connected to the 1 st power supply system, the high-voltage power supply unit is capable of outputting a voltage higher than a rated voltage of the 1 st power supply system or the 2 nd power supply system,

the 2 nd power supply system has:

a switching device capable of switching between a state in which the switching device is connected to the 1 st power supply system so that power can be supplied from the 2 nd low-voltage power supply to the 1 st power supply system, and a state in which the switching device cuts off the 2 nd low-voltage power supply from the 1 st power supply system; and

a vehicle power supply control device that controls the switching device,

The vehicle power supply control device is capable of executing an estimation process of measuring an internal resistance of the 2 nd low-voltage power supply to estimate whether or not it is in a deteriorated state, outputting a signal indicating whether or not the 2 nd low-voltage power supply is in a deteriorated state based on an estimation result of the estimation process,

as the estimation process, the vehicle power supply control apparatus can perform: a 1 st estimation process of estimating an internal resistance of the 2 nd low-voltage power supply when the 2 nd low-voltage power supply is charged; and a 2 nd estimation process of estimating based on the discharge power from the 2 nd low-voltage power supply,

the vehicle power supply control device executes the 2 nd estimation process when the high-voltage power supply portion of the vehicle power supply system is in an on state, and when the high-voltage power supply portion supplies electric power to the 1 st power supply system, and when the state of the vehicle satisfies a predetermined condition.

2. The vehicle power supply system according to claim 1, wherein,

the predetermined condition includes that the temperature of the 2 nd low-voltage power supply is 1 st temperature or lower.

3. The vehicle power supply system according to claim 1, wherein,

the predetermined condition includes that the temperature of the 2 nd low-voltage power supply is 2 nd temperature or higher.

4. The vehicle power supply system according to claim 1, wherein,

the 1 st low-voltage power supply and the 2 nd low-voltage power supply are constituted by batteries capable of charge and discharge,

the prescribed condition includes that the remaining capacity of the battery of the 1 st low-voltage power supply is smaller than the remaining capacity of the battery of the 2 nd low-voltage power supply.

5. The vehicle power supply system according to any one of claims 1 to 4, wherein,

the vehicle power supply control device measures the internal resistance of the 2 nd low-voltage power supply based on the discharge power discharged from the 2 nd low-voltage power supply in a state where the switching device is turned off when the 2 nd estimation process is executed, thereby estimating whether the 2 nd low-voltage power supply is in a degraded state.